English Synonyms Practice Test 4

Straight : extending or moving uniformly in one direction only; without a curve or bend.
Sincere : free from pretence or deceit; proceeding from genuine feelings.
Zigzag : a line or course having abrupt alternate right and left turns.
Doubtful : feeling uncertain about something.
Dubious : hesitating or doubting.

Synonym of Dubious is Doubtful