Definitions for "PASTIME"
That which amuses, and serves to make time pass agreeably; sport; amusement; diversion; as, that great American pastime, baseball.
To sport; to amuse one's self.
a diversion that occupies one's time and thoughts (usually pleasantly); "sailing is her favorite pastime"; "his main pastime is gambling"; "he counts reading among his interests"; "they criticized the boy for his limited pursuits"
A device for promoting dejection. Gentle exercise for intellectual debility.
a precious thing, all the more so when one is alternatingly both player and spectator, allowing one the benefit of both positions
a series of transactions that is complementary (reciprocal), semi-ritualistic, and is mainly intended as a time-structuring activity
Since a pastime is something you do to pass the time, you would expect a double [s] here. Well, there is only one. The second [s] was slipped through the cracks in English orthography long ago.
Keywords:  substitute, game
a substitute for a game
Keywords:  conversation, pre, subject, around, set
a pre-set conversation around a certain subject