English intensifies adjectives with a separate adverb: very tired, bright red, dead serious. Dutch can do that too (heel moe, erg duur), but it has a second, far more colourful strategy: it fuses a fixed intensifying element directly onto the front of the adjective, writing the result as one solid word. Doodmoe, peperduur, knalrood. These prefixes all mean roughly "extremely," but they aren't interchangeable — each one bonds with a particular set of adjectives, carries its own flavour, and sits at its own point on the register scale. Getting the pairing right is one of the things that makes you sound like a native rather than a textbook.
What these prefixes are (and aren't)
Originally most of these intensifiers were nouns or adjectives in their own right: dood (dead), peper (pepper), steen (stone), knal (a bang), bloed (blood). Over time they bleached into pure intensifiers when stuck to an adjective. Doodmoe has nothing to do with death; peperduur has nothing to do with pepper. The literal meaning is gone — only the "extremely" remains.
Two structural facts matter from the start:
- They are written solid, as one word, with no space and no hyphen. This is the single most common written error English speakers make.
- They attach to adjectives (and the adverbs built from them), not to nouns or verbs. You intensify duur (expensive), not huis (house).
Ik ben doodmoe, ik ga meteen naar bed.
I'm dead tired, I'm going straight to bed. One word: doodmoe.
Die nieuwe telefoon is peperduur, dat betaal ik echt niet.
That new phone is ridiculously expensive, I'm really not paying that.
The main prefixes, one by one
dood- ("dead-")
The most productive of all. Dood- attaches to a wide range of adjectives, both physical states and abstract qualities. Note that several dood- combinations have drifted to mean "utterly ordinary / utterly harmless" rather than "very":
- doodmoe — dead tired
- doodeng — terrifying ("dead scary")
- doodziek — deathly ill
- doodsbang — scared to death (note the linking -s-: doods-bang)
- doodgewoon — perfectly ordinary, "nothing special"
- doodleuk — deadpan, "as if it were nothing"
- doodstil — dead quiet
- doodzonde — a real shame (here on a noun, zonde = pity)
Hij vertelde doodleuk dat hij de auto total loss had gereden.
He calmly announced, as if it were nothing, that he'd written off the car.
Het is doodzonde dat je niet kon komen.
It's a real shame you couldn't come.
peper- ("pepper-")
Almost a one-trick prefix: in everyday use it bonds essentially only with duur.
De huizenprijzen in Amsterdam zijn peperduur geworden.
House prices in Amsterdam have become outrageously expensive.
stom- ("dumb-")
Stom- (literally "mute/stupid") intensifies adjectives in the annoyance/drunkenness range. (informal)
- stomvervelend — deadly boring / really annoying
- stomdronken — blind drunk
- stomverbaasd — utterly astonished
- stomtoevallig — by sheer coincidence
Die vergadering was stomvervelend, ik viel bijna in slaap.
That meeting was mind-numbingly boring, I almost fell asleep.
Ik kwam haar stomtoevallig tegen in de supermarkt.
I ran into her by sheer coincidence at the supermarket.
straal- ("beam-")
A very narrow, emphatic intensifier. Its one solidly lexicalised pairing is straalbezopen (the dictionary form); straal- otherwise survives only in a handful of fixed, very informal expressions. (informal, leaning crude with bezopen)
- straalbezopen — completely plastered (the standard, dictionary-listed form)
- straalbezweet — drenched in sweat (heard colloquially, but not as fixed as straalbezopen)
Hij was zaterdag straalbezopen, hij kon niet eens meer op zijn benen staan.
He was completely plastered on Saturday, he couldn't even stand up anymore.
knal- ("bang-")
Specialised for bright colours and a couple of other adjectives. This is your go-to intensifier for vivid colour.
- knalrood — bright red
- knalgeel — bright yellow
- knalgroen, knalblauw, knaloranje
- knalhard — extremely loud / very hard
Ze had knalrode nagels en een knalgele jas aan.
She had bright red nails and a bright yellow coat on.
Zet die muziek niet zo knalhard, de buren klagen.
Don't put that music on so blastingly loud, the neighbours are complaining.
bloed- ("blood-")
Bloed- intensifies temperature, seriousness, and a few emotional adjectives.
- bloedheet — boiling hot
- bloedserieus — dead serious
- bloedmooi — stunningly beautiful
- bloedlink — extremely dangerous / hopping mad (regional nuance)
Het was bloedheet in de trein, alle ramen zaten dicht.
It was boiling hot on the train, all the windows were shut.
Ik meen het bloedserieus, dit is geen grap.
I mean it deadly seriously, this is not a joke.
kei- ("boulder-")
Kei- (literally a cobblestone/boulder) is a broad, youthful intensifier that attaches to almost anything positive. It's strongly informal and somewhat generational/regional (very common with younger speakers and in the south/east). (informal)
- keihard — rock hard / very fast / very loud
- keigoed — really good
- keileuk — really fun
- keigaaf — really cool
Die film was keigoed, je moet 'm echt zien.
That film was really good, you've got to see it.
reuze- ("giant-")
Reuze- (from reus, giant) means "tremendously." It feels slightly older and breezier than kei-. (informal)
- reuzeleuk — tremendous fun
- reuzegezellig — wonderfully cosy/sociable
- reuzehandig — terribly handy
Het was reuzegezellig gisteren, dat moeten we vaker doen.
It was wonderfully cosy yesterday, we should do that more often.
The hartstikke exception
The very common intensifier hartstikke ("totally, completely") behaves differently: it is written as a separate word, not glued on. So you write hartstikke leuk, hartstikke goed, hartstikke bedankt — never hartstikkeleuk. It descends from hard stik(ken) ("choke hard") but is now an opaque, single, indeclinable intensifier that simply sits in front of the adjective like heel does. (informal)
Bedankt voor je hulp, hartstikke aardig van je!
Thanks for your help, that's really kind of you!
Het feest was hartstikke gezellig, jammer dat je weg moest.
The party was great fun, shame you had to leave.
Register: handle with care
Almost every prefix on this page is informal. They belong in speech, texts, and casual writing — not in a job application, an academic essay, or a formal email. In formal register you reach for neutral degree words instead: zeer, uiterst, bijzonder, buitengewoon.
| Informal (prefixed) | Neutral / formal |
|---|---|
| peperduur | zeer duur, kostbaar |
| doodmoe | uitgeput, zeer vermoeid |
| keigoed | uitstekend, zeer goed |
| bloedserieus | volkomen serieus |
There's also an inner register split: peper-, dood-, bloed-, knal- are broadly acceptable in casual speech across generations; kei- and reuze- are more colloquial and age/region-flavoured; straalbezopen and stomdronken are slangy and edge toward crude.
Common Mistakes
❌ Die telefoon is peper duur. → ✅ Die telefoon is peperduur.
That phone is very expensive. The prefix is written solid — no space.
❌ Het was hartstikkeleuk. → ✅ Het was hartstikke leuk.
It was great fun. 'Hartstikke' is the exception — it stays a SEPARATE word.
❌ De lucht was peperblauw. → ✅ De lucht was knalblauw.
The sky was bright blue. Colours take 'knal-', not 'peper-' (which is only for price).
❌ In mijn sollicitatiebrief schreef ik dat de baan keigoed bij me past. → ✅ ...dat de baan uitstekend bij me past.
In my application I wrote that the job suits me perfectly. 'Kei-' is too informal for a formal letter; use 'uitstekend'.
❌ Dat is een doodmoe huis. → ✅ Dat is een doodgewoon huis.
That's a perfectly ordinary house. These prefixes attach to adjectives that fit the meaning — 'doodmoe' (dead tired) can't describe a house; 'doodgewoon' (perfectly ordinary) can.
Key Takeaways
- Intensifying prefixes mean "extremely" and are written solid (one word): doodmoe, peperduur, knalrood.
- Each prefix collocates with a specific set of adjectives — knal- with colours, peper- with duur, bloed- with heat/seriousness, stom- with boredom/drunkenness, dood- most widely.
- hartstikke is the odd one out: written as a separate word.
- Nearly all of these are informal; in formal register use zeer, uiterst, bijzonder, buitengewoon instead.
Now practice Dutch
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Start learning Dutch→Related Topics
- Intensity and Emphasis VocabularyB2 — How Dutch says 'very' across the register scale — neutral heel/erg/zeer, informal hartstikke/ontzettend/mega/super, regional kei-, and the productive intensifying prefixes (doodmoe, peperduur, stomvervelend, spuugzat) — plus 'veel te' for 'far too'.
- Prefixes: Be-, Ver-, Ont-, Her-, On-B2 — Dutch derivational prefixes fall into two families. The inseparable verb prefixes be-, ver-, ont-, her- (and ge-) are unstressed, never split off the verb, and take NO ge- in the past participle (bewerkt, verwerkt, not gebewerkt). The negating prefix on- turns adjectives and nouns into their opposite (onmogelijk, ongeluk, onaardig). This page covers each prefix's meaning, the no-ge- rule, and on- versus niet.
- Compounding: Building Solid WordsB1 — Dutch noun compounds are written as a single solid word (keukentafel, never 'keuken tafel'), and they are head-final: the last element is the head and sets the gender and plural (de tafel gives de keukentafel; het huis gives het zomerhuis). This page covers solid spelling, head-final agreement, the linking letters tussen-s and tussen-n, and the few cases where a hyphen is correct.
- Adjective-Forming SuffixesB1 — Dutch builds adjectives with a small set of productive suffixes. The three that map cleanly onto English are -baar (= -able, eetbaar), -loos (= -less, zinloos), and -achtig (= -ish, roodachtig). The general workhorses -ig (handig, zonnig) and -lijk (vriendelijk, mogelijk) build everyday adjectives, while -isch, -zaam, and -s cover the rest. All of them inflect normally with -e.
- Word Formation in Dutch: OverviewB1 — Dutch builds new words three ways: compounding (gluing words solid, like keukentafel), derivation (adding prefixes and suffixes, like verwerken or vrijheid), and conversion (using a word as a different part of speech, like het eten). This page orients you to all three and shows how parsing a word into its pieces lets you decode and even predict the meaning, gender, and plural of words you have never seen.