furtive

From Middle English furtyve (implied in furtyvely (adverb)), from Middle French furtif, furtive (“furtive, stealthy”) (modern French furtif), from Latin fūrtīvus (“clandestine, furtive, secret; concealed, hidden; stolen”), from fūrtum (“theft; robbery”) (from fūr (“thief”), ultimately from Proto-Indo-European bʰer- (“to bear, carry”)) + -īvus (suffix forming adjectives).