late 15c., from M.Fr. amuser
"divert, cause to muse," from a
"at, to" (but here probably a causal prefix) + muser
"ponder, stare fixedly." Sense of "divert from serious business, tickle the fancy of" is recorded from 1630s, but through 18c. the primary meaning was "deceive, cheat" by first occupying the attention. Bemuse
retains more of the original meaning.