Ben taze kahve kokusuna karşı koyamıyorum.

A helpful breakdown is:

• Ben = I
• taze = fresh
• kahve = coffee
• kokusuna = to its smell / to the smell of it
• karşı koyamıyorum = I can’t resist

So the structure is roughly:

• Ben
• [taze kahve kokusuna]
• karşı koyamıyorum

A more literal gloss would be something like:

• I fresh coffee smell-to resist-can’t-am

But the natural English meaning is simply I can’t resist the smell of fresh coffee.

Yes, it can be omitted.

Turkish verbs already show the subject, and -um in koyamıyorum tells you the subject is I. So:

• Ben taze kahve kokusuna karşı koyamıyorum.
• Taze kahve kokusuna karşı koyamıyorum.

Both are correct.

Including ben adds emphasis or contrast, like:

• I can’t resist it.
• Maybe others can, but I can’t.

So ben is not required for basic grammar here.

Taze kahve kokusu means the smell of fresh coffee.

This is a very common Turkish pattern:

• kahve kokusu = coffee smell / the smell of coffee
• limon suyu = lemon juice
• okul kapısı = school door / the door of the school

So kahve kokusu is a noun compound, not just two separate nouns.

Also, taze comes before the word it modifies. Here taze modifies kahve, so the meaning is:

• fresh coffee
  • smell
• not fresh smell

That is why the whole phrase means the smell of fresh coffee.

Because kahve kokusu is a Turkish noun compound.

In this type of compound, the second noun takes a suffix that looks like a 3rd-person possessive ending:

• koku = smell
• kahve kokusu = coffee smell / the smell of coffee

So -su here is part of the compound structure.

It does not necessarily mean there is a literal his/her/its in English. It is just how Turkish commonly forms expressions like:

• çay bardağı = tea glass
• araba kapısı = car door
• kahve kokusu = coffee smell

So kokusu is the normal form inside this compound.

Because karşı koymak takes the dative case.

The verb pattern is:

• bir şeye karşı koymak = to resist something

So the noun has to be in the dative:

• koku → kokuya
• kokusu → kokusuna

Here:

• kokusu = the smell of coffee
• kokusuna = to the smell of coffee

That -na is the dative ending in this form.

This is because Turkish uses a buffer n after a 3rd-person possessive form before certain case endings.

So:

• kokusu
  • dative
• becomes kokusuna

Not kokusuya

This happens in many words:

• araba-sı → arabasına
• ev-i → evine
• kapı-sı → kapısına

So once you have that possessive/compound ending, Turkish often inserts n before the case ending.

Yes. Karşı koymak is a fixed verb expression meaning:

• to resist
• to stand up against
• to withstand

Literally, the pieces are:

• karşı = against
• koymak = to put

But together, karşı koymak functions as one expression: to resist.

So in this sentence, don’t try to translate karşı and koymak too separately. Learn the whole pattern:

• bir şeye karşı koymak = to resist something

Examples:

• Baştan çıkarmaya karşı koydu. = He/She resisted temptation.
• Buna karşı koyamam. = I can’t resist this.

Koyamıyorum means I can’t put / I’m unable to put, and inside karşı koymak, it becomes I can’t resist.

A simple breakdown is:

• koy- = put
• -ama- = cannot / be unable to
• -yor = present continuous
• -um = I

So:

• koyamıyorum = I can’t / I’m unable to

In the full expression:

• karşı koyamıyorum = I can’t resist

This is an example of the negative potential/ability form.

This is a very important difference.

• karşı koyamıyorum = I can’t resist / I’m unable to resist
• karşı koymuyorum = I’m not resisting / I do not resist

So:

• -amıyorum expresses inability
• -muyorum expresses simple negation

Compare:

• Tatlıya karşı koyamıyorum. = I can’t resist sweets.
• Tatlıya karşı koymuyorum. = I’m not resisting sweets.

The second one could imply choice or behavior. The first one means you are unable to resist.

Because Turkish often uses the present continuous form for current states, repeated tendencies, and everyday truths about oneself.

So koyamıyorum can mean:

• I can’t resist
• I’m unable to resist
• I just can’t resist

It does not have to mean only something happening at this exact second.

A form like koyamam is also possible, but it sounds a bit different:

• karşı koyamıyorum = a lived, ongoing tendency; very natural in conversation
• karşı koyamam = more general, firm, or categorical: I cannot resist

Both can be correct, but koyamıyorum sounds very natural here.

Because Turkish does not use articles the way English does.

There is no direct equivalent of the or a/an in many sentences. Whether something is definite or indefinite is usually understood from context.

So:

• kahve kokusu can mean coffee smell, the smell of coffee, or a coffee smell, depending on context

In this sentence, English naturally uses the:

• the smell of fresh coffee

But Turkish does not need a separate word for that.

Yes, but the nuance changes.

• kahve kokusuna = to the smell of coffee / coffee smell
• kahvenin kokusuna = to the smell of the coffee

The first one is the more general, compound-style expression and is very natural here.

The second one sounds more specific, as if you mean a particular coffee:

• Masadaki kahvenin kokusuna karşı koyamıyorum. = I can’t resist the smell of the coffee on the table.

So in your sentence, kahve kokusuna is the most natural choice for the general idea of the smell of fresh coffee.