noun
A somewhat literary or old-fashioned word for a hobby or activity done to pass the time; often implies a quiet, personal pursuit.
読書は彼の唯一のすさびだ。
Reading is his only pastime.
老後のすさびに絵を描き始めた。
He started painting as a pastime for his old age.
Derived from the verb すさぶ (to become desolate, to do something to distract oneself). The exact derivation is uncertain, but it likely shifted from 'distraction from desolation' to 'pastime'.