To whimper is to make a low, weak crying sound — the small broken noise a person or an animal makes when they are hurt, afraid, or very sad, but not crying loudly. It is quieter than crying and much quieter than sobbing. A dog whimpers at the door. A child whimpers in her sleep. The sound is soft and it usually keeps repeating a little.

It is also used for how a person speaks. If you 'whimper' words, you say them in that same weak, half-crying voice: '"Please don't go," she whimpered.' In writing, this often replaces 'said', so the reader hears the voice.

The noun is the same word: 'a whimper', the sound itself. Here you should know a very common phrase: 'not with a bang but a whimper'. It means something ended in a small, sad, disappointing way instead of a big dramatic one — 'The show ended with a whimper' means it just faded away, and nobody cared much. This phrase comes from a famous poem, and English speakers use it constantly for failed projects, teams, and elections.

One more thing worth knowing: when you use whimper about an adult who is complaining, it sounds unkind — you are saying their complaint is weak and childish. So be careful using it about people. Used about animals and small children, it is gentle and full of sympathy.