Origin: back formation from
confused (since early 19th century), ME
confused < AF
confus (with
-ed -ed 2 maintaining participial sense) < L
confūsus, ptp. of
confundere; see confound 
Related forms: con⋅fus⋅a⋅ble, adjective
con⋅fus⋅a⋅bil⋅i⋅ty, noun
con⋅fus⋅a⋅bly, adverb
con⋅fus⋅ed⋅ness, noun
Synonyms:
1. mystify, nonplus. Confuse, disconcert, embarrass imply temporary interference with the clear working of one's mind. To confuse is to produce a general bewilderment: to confuse someone by giving complicated directions. To disconcert is to disturb one's mind by irritation, perplexities, etc.: to disconcert someone by asking irrelevant questions. To embarrass is to cause one to be ill at ease or uncomfortable, so that one's usual judgment and presence of mind desert one: to embarrass someone by unexpected rudeness. 4. mortify, shame. 5. disarray, disarrange, disturb.
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