Slightly

ATAD

Think of how you might describe something that’s just a little off-center.

The clue "Slightly" hints at the word "a tad," which is a casual phrase meaning "a little bit." In crosswords, "a tad" is often shortened to "ATAD" by removing the space. The answer plays on the idea of taking a common expression and compacting it into a single word for the puzzle’s format.