means A person who skillfully and often deceptively controls or influences others to serve their own ends.

from From Latin 'manus' (hand) — the same hand that gives us 'manual,' 'manufacture,' and 'manuscript.' It came through French 'manipule,' a handful, into 'manipuler,' to handle. Originally the manipulator was a literal handler — a pharmacist working substances by hand, a craftsman shaping material. The figurative sense of 'one who handles people' is a later, darker turn: the same dexterous fingers, now working you instead of clay.