Is it ensure, insure, or assure?
1660s, "painless," from Late Latin indolentem (see indolence). Sense of "living easily" is 1710, from French indolent. Related: Indolently.
indolent in·do·lent (ĭn'də-lənt)adj.
Disinclined to exert oneself; habitually lazy.
Causing little or no pain, as a tumor.
Slow to heal, grow, or develop, as an ulcer; inactive.