Traditionally, a finite verb (from fīnītus, past participle of fīnīre - to put an end to, bound, limit) is the form "to which number and person appertain", in other words, those inflected for number and person. Verbs were originally said to be finite if their form limited the possible person and number of the subject.
A more recent concept treats a finite verb as any verb that heads a simple declarative sentence. Under that newer articulation, finite verbs often constitute the locus of grammatical information regarding gender, person, number, tense, aspect, mood, and voice. Finite verbs are distinguished from non-finite verbs, such as infinitives, participles, gerunds etc., which generally mark these grammatical categories to a lesser degree or not at all, and which appear below the finite verb in the hierarchy of syntactic structure.
The finite verbs are in bold in the following sentences, and the non-finite verbs are underlined:
Verbs appear in almost all sentences.
This sentence is illustrating finite and non-finite verbs.
The dog will have to be trained well.
Tom promised to try to do the work.
In many languages (including English), there can be one finite verb at the root of each clause (unless the finite verbs are coordinated), whereas the number of non-finite verbs can reach up to five or six, or even more, e.g.
He was believed to have been told to have himself examined.
Finite verbs can appear in dependent clauses as well as independent clauses:
John said that he enjoyed reading.
Something you make yourself seems better than something you buy.
Most types of verbs can appear in finite or non-finite form (and sometimes these forms may be identical): for example, the English verb go has the finite forms go, goes, and went, and the non-finite forms go, going and gone. The English modal verbs (can, could, will, etc.) are defective and lack non-finite forms.
It might seem that every grammatically complete sentence or clause must contain a finite verb.