In Finnish grammar, the momentane is a verb aspect indicating that an occurrence is sudden and short-lived.
Finnish has a number of momentane markers; they differ in the valency and voice of the verbs they produce, but all indicate sudden, short-lived occurrences; for example, the verb ammahtaa ('to dash ahead suddenly'; not said of a person) is an anticausative, momentane version of ampua ('to shoot').
Verbs with momentane markers are considered independent words, and native speakers rarely analyze them, but do synthesize them.
For example: Another note is that the root may not be a fully formed verb, but mere onomatopoeia, e.g. pam+auttaa "to bang (something suddenly once)" or in frequentative form pam+autella "to bang (something suddenly multiple times)".
The markers are affected by consonant gradation, as illustrated by this pair of first infinitives vs. second-person indicatives: pamahtaa ~ pamahdat, pamauttaa ~ pamautat / pamautella ~ pamauttelet.