"theft; wrongful or fraudulent taking of the personal goods of another with felonious intent," late 15c., from Anglo-French larcin (late 13c.), Old French larrecin, larcin "theft, robbery" (11c.), from Latin latrocinium "robbery, freebooting, highway-robbery, piracy," from latro "robber, bandit," also "hireling, mercenary," ultimately from a Greek source akin to latron "pay, hire, wages," from a suffixed form of PIE root *le- (1) "to get" (source also of Greek latreia "worship, service paid to the gods, hired labor," latron "pay, hire," latris "servant, worshipper").
Perhaps with -y (3) added in English or else the word was altered by influence of burglary, felony. Formerly distinguished into grand larceny, involving property valued in excess of a stated amount, and petty larceny.
word-forming element meaning "one who does or makes," also used to indicate adherence to a certain doctrine or custom, from French -iste and directly from Latin -ista (source also of Spanish, Portuguese, Italian -ista), from Greek agent-noun ending -istes, which is from -is-, ending of the stem of verbs in -izein, + agential suffix -tes.
Variant -ister (as in chorister, barrister) is from Old French -istre, on false analogy of ministre. Variant -ista is from Spanish, popularized in American English 1970s by names of Latin-American revolutionary movements.