A készenléti üzemmód pazarló.

A is the Hungarian definite article, equivalent to the in English.

In A készenléti üzemmód pazarló, a means the, so the sentence is talking about standby mode as a specific/general known thing.

A useful detail:

• a is used before consonant sounds
• az is used before vowel sounds

For example:

• a ház = the house
• az autó = the car

In Hungarian, the verb to be is often omitted in the present tense, third person.

So:

• A készenléti üzemmód pazarló. literally looks like
• The standby mode wasteful.

But it naturally means:

• Standby mode is wasteful.

This omission happens when the sentence is equational or descriptive in the present tense:

• A könyv érdekes. = The book is interesting.
• A szoba nagy. = The room is big.

But in other persons, the verb appears:

• Pazarló vagyok. = I am wasteful.
• Pazarló vagy. = You are wasteful.

It is a noun phrase meaning standby mode.

It is made of:

• készenléti = standby / readiness-related
• üzemmód = operating mode, mode

So Hungarian is building the idea as something like:

• readiness-mode

This is very common in Hungarian: technical concepts are often formed by combining descriptive elements into one phrase.

Yes, készenléti functions as an adjective here.

It comes from készenlét, which means readiness, standby, or state of being ready.
The ending -i often turns a noun into an adjective meaning related to or of something.

So:

• készenlét = readiness / standby
• készenléti = standby-related, readiness-related

This kind of formation is very common:

• iskola = school
• iskolai = school-related / school
• nyár = summer
• nyári = summer

Yes, üzemmód is one word.

It is a compound noun:

• üzem = operation, functioning, plant, running
• mód = way, mode, manner

Together:

• üzemmód = operating mode / mode

Hungarian very often writes compounds as a single word where English uses two words:

• üzemmód = operating mode
• számítógép = computer
• mosógép = washing machine

Pazarló is an adjective here, meaning wasteful.

It comes from the verb pazarol, which means to waste.

So the pattern is roughly:

• pazarol = waste
• pazarló = wasteful / wasting

The ending -ó / -ő often creates a participle-like adjective in Hungarian, something like one that does X or X-ing.

For example:

• tanul = study
• tanuló = studying; also student/learner in some contexts
• függ = depend/hang
• függő = dependent / hanging

Here, pazarló means something like wasting or more naturally wasteful.

Because in this sentence, pazarló is not directly modifying the noun inside the noun phrase. It is the predicate of the sentence.

Compare these two structures:

1. Attributive adjective: adjective directly before the noun

   • a pazarló üzemmód = the wasteful mode

2. Predicate adjective: adjective tells you what the subject is like

   • Az üzemmód pazarló. = The mode is wasteful.

In your sentence, A készenléti üzemmód is the subject, and pazarló is what is being said about it.

Yes. Hungarian word order is flexible, and changing it often changes the focus or emphasis rather than the basic meaning.

For example:

• A készenléti üzemmód pazarló. = neutral statement
• Pazarló a készenléti üzemmód. = emphasis on wasteful

The second version may sound like:

• It is wasteful, this standby mode or
• Standby mode is what's wasteful

So both are possible, but the original sentence is the more neutral, dictionary-style statement.

Because it is in the basic dictionary form here, with no case ending.

Hungarian uses case endings when a noun has a grammatical role like in, to, with, from, and so on. But in this sentence, A készenléti üzemmód is the subject, so no extra ending is needed.

Examples with endings:

• üzemmódban = in mode
• üzemmódot = mode as a direct object
• üzemmódhoz = to the mode

But here:

• A készenléti üzemmód pazarló. the noun phrase is just the subject.

The accent marks in Hungarian mostly show vowel length, and vowel length matters.

In this sentence:

• é is a long e
• ó is a long o
• ü is like German ü or French u
• ú would be a long u, though it does not appear here

A rough guide:

• készenléti ≈ kay-sen-LAY-tee
• üzemmód ≈ UU-zem-mode
• pazarló ≈ PAW-zar-low

A few important points:

• stress in Hungarian usually falls on the first syllable
• long and short vowels are different sounds, not just stylistic spelling differences

So:

• o and ó are different
• e and é are different

Yes, it is grammatical and natural, especially in a neutral or somewhat technical context.

That said, Hungarian also commonly uses:

• készenléti mód instead of
• készenléti üzemmód

Both are understandable. Üzemmód can sound a bit more technical or formal, like operating mode, while mód is shorter and often more everyday in device-related contexts.

So the sentence sounds fine, especially in writing, technical discussion, or formal explanation.

You would add nem before the predicate:

• A készenléti üzemmód nem pazarló. = Standby mode is not wasteful.

This is the normal way to negate this kind of sentence.

Compare:

• A telefon drága. = The phone is expensive.
• A telefon nem drága. = The phone is not expensive.

Normally, no. The usual adjective is pazarló.

Even though the verb is pazarol, the established adjective is pazarló, not pazaroló in normal usage.

So:

• pazarol = to waste
• pazarló = wasteful

This is just something to learn as a vocabulary item. Hungarian word formation is often regular, but some forms become standard and others do not.