Real Dictionary

swim
If something is swimming in liquid or is swimming with liquid, it is surrounded by and covered with it.
verb: If objects swim, they seem to be moving backwards and forwards, usually because you are ill.
verb: If you swim a race, you take part in a swimming race.
verb: If you swim a stretch of water, you keep swimming until you have crossed it.
verb: If your head is swimming, you feel unsteady and slightly ill.
verb: When a fish swims, it moves through water by moving its body.
verb: When you swim, you move through water by making movements with your arms and legs.

swim in American English
intransitive verb: to move in water by movements of the limbs, fins, tail, etc.
noun: an act, instance, or period of swimming
transitive verb: to move along in or cross (a body of water) by swimming

swim in American English 1
to move through water by movements of the arms and legs, or of flippers, fins, tail, etc.

swim in American English 2
the condition of being dizzy; dizzy spell
to be dizzy

swim in British English
verb: to move along in water, etc, by means of movements of the body or parts of the body, esp the arms and legs, or (in the case of fish) tail and fins