The term curt describes speech or manner as impolitely brief or sudden. To identify its antonym, we require a word indicating excessive talkativeness or expressiveness. Let's analyze the provided choices:
Short - This term mirrors curt in its implication of brevity. It is not an antonym.
Abrupt - This word is synonymous with curt, as both denote a sudden or terse demeanor. It is not an antonym.
Concise - Analogous to curt, concise signifies conveying much information with few words. It is not an antonym.
Voluble - This word means speaking or spoken at length and with fluency. It stands in direct opposition to being brief or abrupt, thus serving as the antonym for curt.
Consequently, the appropriate answer is voluble.