long, short
broad (often figurative), thick
I will outline in broad strokes our main ideas.

narrow, thin
bold, vigorous
She caught his likeness with a few bold pen strokes.

even
deft
quick, slow
downward, upward
horizontal, vertical
brush (usually brushstroke), pen, pencil

with a stroke of the pen
With a stroke of the pen our names were removed from the register.

fast, quick
slow, smooth
powerful
The Romanian rowers pulled ahead with powerful strokes.

backhand, forehand (in tennis, etc.)
downward, upward

play
He played some powerful backhand strokes throughout the game.

by a stroke, two strokes, etc. (in golf)
Woods leads by two strokes.

a stroke, two strokes, etc. ahead, a stroke, two strokes, etc. behind (in golf)

swim (AmE), swimming
long, short
He swam back with long, slow strokes.

fast, slow
powerful, strong

do, swim
You can't swim more than four strokes before you reach the other side.

acute, crippling, debilitating, disabling (esp. BrE), massive, serious
mild, minor, slight
fatal, non-fatal
recurrent
This regimen substantially reduces the risks of recurrent stroke.

have, suffer
She had a massive stroke and lost her speech.

leave sb …
The stroke left him in a wheelchair.

patient, survivor, victim
prevention

sudden
I had a sudden stroke of inspiration.

have

at a stroke, at one stroke
They lost half their fortune at a stroke.

stroke of
a stroke of genius

a stroke of bad luck, a stroke of fortune, a stroke of good fortune, a stroke of good luck, a stroke of luck