strain

an intense or violent exertion

use to the utmost; exert vigorously or to full capacity

“Don't strain your mind too much”

a group of organisms within a species that differ in trivial ways from similar groups

“a new strain of microorganisms”

a special variety of domesticated animals within a species

“he created a new strain of sheep”

the general meaning or substance of an utterance

to exert much effort or energy

“straining our ears to hear”

an effortful attempt to attain a goal

rub through a strainer or process in an electric blender

alter the shape of (something) by stress

nervousness resulting from mental stress

“his responsibilities were a constant strain”

injury to a muscle (often caused by overuse); results in swelling and pain