cantrip
A spell or incantation; a trifling magic trick.
That shaw’d the dead in their last dresses; And by some devilish cantrip slight Each in its cauld hand held a light […]
Coffins stood round, like open presses,A wilful piece of trickery or mischief.
A minor spell, typically one that can be cast without preparation.
Where it comes from
From Middle Scots cantrip, cantrap (“a magic charm; a trick”). Further origin obscure, but likely a corruption of Scottish Gaelic canntaireachd (identical to Irish cantaireacht), referring to a system of musical notation consisting of a series of otherwise meaningless syllables memorised by pipers in learning their tunes; this was then used similarly to abracadabra. Regardless of details, ultimately derived from Latin cantō (“to sing, chant, play an instrument”).
Adapted from the Wiktionary entry cantrip (CC BY-SA 4.0).