Tämä idea on outo.

Finnish does not have articles like a, an, or the.

So:

• idea can mean idea, an idea, or the idea
• the exact meaning depends on context

In this sentence, English naturally uses this idea is strange, but Finnish simply says:

• Tämä idea on outo.

The word tämä already makes it specific: this idea.

Tämä means this.

It is a demonstrative word used to point to something near the speaker, or something currently being discussed.

In this sentence:

• tämä idea = this idea

A useful comparison:

• tämä = this
• tuo = that
• se = often it / that, depending on context

So you could compare:

• Tämä idea on outo. = This idea is strange.
• Tuo idea on outo. = That idea is strange.

On is the third-person singular form of the verb olla, which means to be.

So:

• minä olen = I am
• sinä olet = you are
• hän on = he/she is
• tämä idea on = this idea is

In the sentence:

• Tämä idea on outo.
• literally: This idea is strange.

Even though idea is not a person, Finnish still uses the same on form for singular third person subjects.

Outo is an adjective meaning strange, odd, or weird.

Here it is the predicate adjective, because it comes after on and describes the subject:

• Tämä idea = the subject
• on = is
• outo = strange

In a basic singular sentence like this, the adjective is in its dictionary form, which is the nominative singular:

• idea on outo = the idea is strange

So nothing special has happened to outo here—it is just in its basic form.

This is the most neutral Finnish word order for this sentence:

• Tämä idea = subject
• on = verb
• outo = complement

So it follows a pattern similar to English:

• This idea is strange.

Finnish word order is more flexible than English, but changing it often changes the emphasis.

For example:

• Tämä idea on outo. = neutral statement
• Outo tämä idea on. = more marked; something like Strange, this idea is
• Tämä on outo idea. = This is a strange idea

That last sentence is different in structure:

• Tämä idea on outo = the idea is strange
• Tämä on outo idea = this is a strange idea

Both are correct, but they are not exactly the same sentence.

Yes. Idea is a normal Finnish word, borrowed long ago from the same international source as English idea.

It is fully used as a Finnish noun and can be declined.

Some forms:

• idea = idea
• idean = of the idea / idea's
• ideaa = idea (partitive)
• ideat = ideas

So even though it looks familiar to an English speaker, it behaves like a regular Finnish noun in grammar.

A rough pronunciation guide:

• tämä ≈ TAE-mae
• idea ≈ EE-de-ah
• on ≈ on
• outo ≈ OW-to

A few important points:

• ä is not the same as English a
• ä is pronounced more like the vowel in British cat for many speakers, though not exactly
• Finnish stress usually falls on the first syllable

So:

• TÄ-mä
• I-de-a
• OU-to

Also, Finnish pronunciation is usually very regular: words are generally pronounced as they are written.

Outo can cover several similar English words, depending on context:

• strange
• odd
• weird
• unusual

Its tone depends on the situation.

For example:

• Tämä idea on outo. could mean:
  • This idea is strange.
  • This idea is odd.
  • This idea is weird.

If the context is light, it may just mean unusual. If the context is more negative, it can sound closer to weird.

You use the Finnish negative verb ei and the main verb changes form.

So:

• Tämä idea on outo. = This idea is strange.
• Tämä idea ei ole outo. = This idea is not strange.

Notice:

• positive: on
• negative: ei ole

That is a very common Finnish pattern with olla:

• on = is
• ei ole = is not

In Finnish, yes/no questions are often made by adding -ko/-kö to the verb.

So:

• Tämä idea on outo. = This idea is strange.
• Onko tämä idea outo? = Is this idea strange?

Notice that the verb comes first in this question:

• Onko = is?

This is one of the most common question patterns in Finnish.

Yes, the sentence would change.

Singular:

• Tämä idea on outo. = This idea is strange.

Plural:

• Nämä ideat ovat outoja. = These ideas are strange.

You can notice three changes:

• tämä → nämä (this → these)
• idea → ideat (idea → ideas)
• on → ovat (is → are)

And the adjective also changes:

• outo → outoja

That last change is very useful to notice, because predicate adjectives in Finnish do not always stay in the basic form when the sentence becomes plural.

Sometimes, yes, but it is not exactly the same as tämä idea.

• tämä idea = this idea
• se idea often means that idea in spoken Finnish, or simply refers to a previously mentioned idea

In standard written Finnish, tämä is the clearer choice for this.

So for a learner, this is the safest match:

• Tämä idea on outo. = This idea is strange.

You may hear se a lot in everyday speech, but it is better to learn the standard form first.