strain has 35 distinct synonyms spread across 18 of its 20 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. Its one recorded opposite is unstrain.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
(physics) deformation of a physical body under the action of applied forces
difficulty that causes worry or emotional tension
“she endured the stresses and strains of life”
a succession of notes forming a distinctive sequence
“she was humming an air from Beethoven”
(psychology) nervousness resulting from mental stress
“his responsibilities were a constant strain”
a special variety of domesticated animals within a species
“he experimented on a particular breed of white rats”
(biology) a group of organisms within a species that differ in trivial ways from similar groups
“a new strain of microorganisms”
injury to a muscle (often caused by overuse); results in swelling and pain
the act of singing
“with a shout and a song they marched up to the gates”
Synonyms, antonyms and the broader and narrower relations for strain come from Princeton University’s WordNet. Full sources and licences.
use to the utmost; exert vigorously or to full capacity
“He really extended himself when he climbed Kilimanjaro”