Slå literally means "to strike, hit, beat" — but like English strike and beat, it spawns a sprawling family of idioms whose meaning you cannot guess from the parts. Slå op can mean "look up (a word)" or "break up (with a partner)"; slå til can mean "be enough," "strike," or "take an offer." For a C1 learner the work is twofold: learn the senses, and master the word order of the particle, because where the object goes is not the same as in English. (Forms: present slår, past slog, perfect har slået.)
Sense 1: physical striking and its targets
The literal sense underlies a set of everyday collocations about hitting, mowing, and hurting.
| Collocation | Meaning |
|---|---|
| slå græsset | mow the lawn |
| slå sig | hurt oneself (by knocking into something) |
| slå ihjel | kill (also: 'kill time') |
| slå en rekord | break a record |
Jeg når lige at slå græsset, før det begynder at regne.
I'll just manage to mow the lawn before it starts raining.
Pas på trinnet — jeg slog mig der i går.
Mind the step — I hurt myself there yesterday.
Hun slog den gamle rekord med to sekunder.
She broke the old record by two seconds.
Sense 2: slå op — look up vs. break up
Slå op is a classic two-meaning idiom. With a thing as object, it means "look up" (a word, a fact, a phone number). With med + a person, it means "break up."
Jeg slår lige ordet op i ordbogen.
I'll just look the word up in the dictionary.
Har du hørt det? Mette har slået op med Jonas.
Have you heard? Mette has broken up with Jonas.
The word order is the crux. When the object is a full noun, it can sit either before or after op, but when it is an unstressed pronoun it must come before the particle:
Jeg slår det op.
I'll look it up.
The form Jeg slår op det is impossible — a light, unstressed pronoun can never follow the particle. With a heavy noun phrase, slå ordet op and slå op ordet are both heard, but slå ordet op is the safer, more idiomatic default.
Sense 3: slå til and other switches
Slå til is genuinely polysemous. Watch the context:
| Use | Meaning |
|---|---|
| slå til (om mængde) | be enough, suffice |
| slå til (om tilbud) | take the offer, jump at it |
| slå til (om angreb) | strike (e.g. police, a thief) |
| slå noget til / fra | switch something on / off |
To flasker vin slår nok ikke til, når vi bliver tolv.
Two bottles of wine probably won't be enough now that there'll be twelve of us.
Tilbuddet gælder kun i dag, så jeg slog til med det samme.
The offer is only valid today, so I jumped at it straight away.
Husk at slå alarmen til, når du går.
Remember to switch the alarm on when you leave.
Husk at slå varmen fra, når du forlader sommerhuset.
Remember to switch the heating off when you leave the summer cottage.
Sense 4: change, settle, fail, champion
A final cluster spreads further from the literal sense.
| Collocation | Meaning |
|---|---|
| slå fejl | fail, go wrong |
| slå sig ned | settle down (in a place) |
| slå om | change, switch (weather, mood, language) |
| slå et slag for | champion, make a case for |
| det slår mig at… | it strikes me that… |
Planen slog fejl, fordi vejret pludselig slog om.
The plan failed because the weather suddenly changed.
Efter mange år i udlandet slog de sig ned i en lille by på Fyn.
After many years abroad, they settled down in a small town on Funen.
Borgmesteren ville slå et slag for mere cykelvenlig infrastruktur.
The mayor wanted to make a case for more bike-friendly infrastructure.
Det slår mig, at vi aldrig fik svar på det første spørgsmål.
It strikes me that we never got an answer to the first question.
Common Mistakes
❌ Mette har brudt op med Jonas.
Incorrect — 'break up' with a partner is 'slå op med', not a calque of English 'break'.
✅ Mette har slået op med Jonas.
Mette has broken up with Jonas.
❌ Jeg slår op det i ordbogen.
Incorrect word order — an unstressed pronoun/short object cannot follow the particle.
✅ Jeg slår det op i ordbogen.
I'll look it up in the dictionary.
❌ Planen faldt fejl.
Incorrect — the fixed phrase for 'go wrong' is 'slå fejl', not 'falde fejl'.
✅ Planen slog fejl.
The plan went wrong.
❌ Husk at tænde alarmen til.
Incorrect — the collocation is 'slå til' (switch on a device/system), and the particle is redundant with 'tænde'.
✅ Husk at slå alarmen til.
Remember to switch the alarm on.
❌ Det rammer mig, at vi glemte det.
Incorrect — for a thought occurring to you, Danish uses 'det slår mig at', not 'det rammer mig'.
✅ Det slår mig, at vi glemte det.
It strikes me that we forgot it.
Key Takeaways
- slå idioms must be learned whole — the literal "strike" rarely predicts the meaning (slå op = look up / break up; slå til = suffice / strike / take an offer).
- Unstressed pronoun objects always come before the particle: slå *det op, never *slå op det.
- "Break up with someone" is slå op med — don't calque English break.
- det slår mig, at… is the idiom for a realisation occurring to you; ramme (hit) is wrong here.
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Start learning Danish→Related Topics
- Collocations: An OverviewB2 — Why Danish pairs specific light verbs (tage, gøre, få, lave, holde) with specific nouns, and how to learn these fixed combinations instead of translating word-for-word.
- SlåB1 — Full reference for the strong verb slå ('hit, strike, beat, mow'), its irregular past slog, and its many idiomatic particle verbs.
- Slå opB2 — Full reference for the phrasal verb slå op — principal parts of the strong verb slå, its four senses (look up, break up, put up, open a book), particle stress, and word order with object pronouns.