Final answer:
The antonym of the word 'frank' is option c. 'ambiguous.' 'Frank' denotes clear and straightforward communication, whereas 'ambiguous' means something that is unclear or vague, suggesting the opposite quality.
Step-by-step explanation:
When looking for the antonym of the word 'frank,' which suggests openness and straightforwardness, the correct choice would be the word that conveys the opposite meaning. Among the options given:
- Blunt - suggests a similar openness or lack of filtering.
- Bold - usually means courageous or willing to take risks which is not the opposite of frank.
- Ambiguous - refers to something that is unclear, vague, or open to more than one interpretation, which can be seen as the opposite of being clear and straightforward like 'frank.'
- Direct - is a synonym for frank, indicating straightforwardness.
Therefore, the word that is an antonym of 'frank' is C) Ambiguous.