Tämä ei ole omani.

This is not mine.

Breakdown of Tämä ei ole omani.

• olla: to be
• tämä: this
• ei: not
• omani: mine

Questions & Answers about Tämä ei ole omani.

What does each word in Tämä ei ole omani do?

• Tämä = this
• ei = the negative verb, here not
• ole = the form of olla (to be) used after a negative verb
• omani = mine / my own one

So the structure is basically:

subject + negative verb + main verb + complement

Here, omani is the part that says whose thing it is.

Why is it ei ole and not ei on?

Because Finnish does not negate verbs by just adding a separate word like English not. It uses a special negative verb.

With olla (to be), the pattern is:

• on = is
• ei ole = is not

So ei carries the negation, and ole is the special form used with it.

A few related examples:

• olen = I am → en ole = I am not
• olet = you are → et ole = you are not
• on = he/she/it is → ei ole = he/she/it is not

So *ei on is not grammatical Finnish.

What exactly does omani mean?

Omani comes from:

• oma = own
• -ni = my

So, literally, it is something like my own one.

In natural English, that usually becomes simply mine.

This is a very useful Finnish pattern. Related forms include:

• omasi = yours
• omansa = his/hers/theirs
• omamme = ours
• omanne = yours (plural/formal)

Why is there no noun after omani?

Because the noun is understood from context.

Finnish often leaves out a noun when it is already clear what object is being talked about. So omani can stand for things like:

• my book
• my coat
• my phone
• my bag

depending on the situation.

So if everyone knows you are talking about, for example, a jacket, then omani means something like my one / mine without repeating jacket.

What form or case is omani here?

Here omani is functioning as a predicative complement after olla (to be).

The base form is oma, and the possessive suffix -ni is added:

oma + ni = omani

So this is not an object form. It is the form used in a sentence like This is mine or This is not mine.

A learner may expect some extra ending, but in this sentence omani is the normal form.

Could I also say Tämä ei ole minun or Tämä ei ole minun omani?

Yes.

All of these are possible, but they are slightly different in feel:

• Tämä ei ole minun.
  A very common way to say This isn't mine.

• Tämä ei ole omani.
  Also natural. It can sound a bit more like This isn't the one that is mine or This isn't my own one.

• Tämä ei ole minun omani.
  More emphatic or contrastive. The ownership is marked twice, so it can feel stronger: This is not mine, it's someone else's.

In many real situations, the differences are small, but omani is especially useful when Finnish wants a stand-alone word similar to English mine.

Why is the sentence using tämä?

Tämä means this, usually referring to something close to the speaker or something the speaker is directly pointing to or focusing on.

Other choices are possible in other contexts:

• tämä = this
• tuo = that
• se = it / that

So you could compare:

• Tämä ei ole omani. = This isn't mine.
• Tuo ei ole omani. = That isn't mine.
• Se ei ole omani. = That/it isn't mine.

For a learner, the main point is that tämä tells you which thing is being discussed.

Is this standard Finnish, and what might people say in everyday speech?

Tämä ei ole omani is good standard Finnish.

In everyday spoken Finnish, people often shorten it. A very common casual version would be:

• Tää ei oo mun.

Changes there are:

• tämä → tää
• ei ole → ei oo
• minun → mun

So the sentence you were given is a useful standard model, while spoken Finnish often uses shorter forms.