The Oxford Thesaurus An A-Z Dictionary of Synonyms - suspiciousadj.

1) doubtful, in doubt, dubious, questionable, debatable, suspect(ed) , under suspicion, open to doubt or question or misconstruction, Colloq shady, fishy: There is something very suspicious about his behaviour. 2) mistrustful, distrustful, doubtful, in doubt, sceptical, suspecting, disbelieving, unbelieving, leery, apprehensive, wary, uncertain, uneasy: I was suspicious of Douglas from the very beginning.