early 14c., "discomfited, routed, defeated" (of groups), serving at first as an alternate pp. of confound
, as Latin confusus was the pp. of confundere "to pour together, mix, mingle; to join together;" hence, figuratively, "to throw into disorder; to trouble, disturb,
upset." The Latin pp. also was used as an adjective, with reference to mental states, "troubled, embarrassed," and this passed into O.Fr. as confus "dejected, downcast, undone, defeated, discomfited in mind or feeling," which passed to M.E. as confus (14c.; e.g. Chaucer: "I am so confus, that I may not seye"), which then was assimilated to the English pp. pattern by addition of -ed. Of individuals, "discomfited in mind, perplexed," from mid-14c.; of ideas, speech, thought, etc., from 1610s. By mid-16c., the word seems to have been felt as a pure adj., and it evolved a back-formed verb in confuse
. Few English etymologies are more confused.