What is the X in X-mas?
c.1400, from Old French spasme, from Latin spasmus "a spasm," from Greek spasmos "a spasm, convulsion," from span "draw up, tear away, contract violently, pull," from PIE *spe- "stretch." Figurative sense of "a sudden convulsion" (of emotion, politics, etc.) is attested from 1817.
1900, from spasm (n.). Related: Spasmed; spasming.
A sudden involuntary contraction of a muscle or group of muscles.
A muscle spasm.