Which term means impossible to penetrate?

• A. IMPERIOUS
• B. FRUGALITY
• C. GARRULOUS
• D. FOMENT

Answer: (A)

Understanding how prefixes and roots signal meaning helps here. The phrase “impossible to penetrate” points to a word built from im- (not) and a root meaning to allow passage, giving the sense of not allowing passage through. That yields words like impervious or impenetrable.

Among the given options, the form that looks like it could fit is imperious, but its meaning is not about passage or penetration. Imperious means arrogant or domineering—giving orders, not being impermeable. The other options describe thrift (frugality), talkativeness (garrulous), and to stir up or incite (foment), none of which match the sense of something that cannot be penetrated.

So the accurate term for “impossible to penetrate” would be impervious (or impenetrable). The listed choices don’t provide that exact meaning, so none of them truly fit the prompt.