The most common and most likely answer to this crossword clue is the 6 plus 7 letter word ROLLER COASTER
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More clues leading to the result ROLLER COASTER
Buddy explains!
The straight part
We know that "a 1ac feature" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case a 1ac feature = roller coaster.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does ROLLER COASTER mean?
ROLLER COASTER noun- An amusement ride consisting of a buggy on a track that rises, falls, twists and turns.
- (by extension) Any situation in which there are ups and downs, or violent changes.