Perfunctory
Perfunctory (pẽr*funk"to*ry) , adjective
[Latin perfunctorius, from perfunctus dispatched, past participle of perfungi to discharge, dispatch; per (see Per) + fungi to perform. See Function.]
1.
Done merely to get rid of a duty; performed mechanically and as a thing of rote; done in a careless and superficial manner; characterized by indifference; as, perfunctory admonitions; a perfunctory greeting. — Macaulay
2.
Hence: Mechanical; indifferent; listless; careless.
Perfunctory in his devotions.