Other forms: swimming, swam, swims, swum
To swim is to move through water using your arms and legs. Swim a length, swim in the sea, learn to swim. It is irregular: swim, swam, swum.
Those three forms are worth drilling, because swum is the one people avoid by rephrasing. Note go swimming, which is the ordinary way to describe the activity, and that a swim is countable: have a swim. The figurative uses are all about being overwhelmed — my head is swimming, swimming in paperwork — and sink or swim means to succeed or fail with no help offered.
1verbswimTo move through water using arms and legs.
“She swims a mile every morning.”
2nounperiodA period of swimming.
“We went for a swim before breakfast.”
3verbfeelTo feel dizzy, or to be overwhelmed.
“My head was swimming by the end of the meeting.”
Too few real examples of this word to estimate which sense is commonest.
swim is a way of moving through water.
Old English swimman comes from a Proto-Indo-European root meaning to move or be in motion, and the same root may lie behind swamp and sound in the sense of a channel of water. It has meant exactly this since before English was English.
Proto-Indo-European
*swem(bʰ)- — to be unsteady, move, swim
Proto-Germanic
*swimmaną — to swim
Proto-West Germanic
*swimman
Old English
swimman — to swim, float
Middle English
swymmen
English, today
swim
From Middle English swymmen, from Old English swimman (“to swim, float”) (class III strong verb; past tense swamm, past participle geswummen), from Proto-West Germanic swimman, from Proto-Germanic swimmaną (“to swim”), from Proto-Indo-European swem(bʰ)- (“to be unsteady, move, swim”). 2 Cognate with frr sweem, swome, swume, swumi, swumme, swääm (“to swim”), stq and West Frisian swimme (“to swim”), Dutch zwemmen (“to swim”), German schwimmen (“to swim”), li schwämme, zwömme (“to swim”), Low German swimmen (“to swim”), lb schwammen (“to swim”), wym švymma, śwyma, śwymma (“to swim”), Yiddish שווימען (“to swim”), Danish and Norwegian Bokmål svømme (“to swim”), Faroese svimja (“to swim”), nrn suma (“to swim”), Norwegian Nynorsk svemja, svemje, svømma, svømme, symja, symje (“to swim”), Swedish simma (“to swim”).
Etymology from Wiktionary, CC BY-SA