Multiple choice Directions: Fill in the blank with the correct word. As _________ as mustard. keen bitter vivid pungent Reveal answer Fill a bubble to check yourself A Correct answer Explanation 'As keen as mustard' is an idiom where 'keen' means eager, enthusiastic, or sharp. Mustard was historically valued for its strong flavor and 'bite.' The other options describe mustard's qualities but are not part of the fixed phrase.