26 across
Not
simple,
so
restive
(6)
Not simple, so restive (6)
hints
0
checks
0
hints
The definition is at the end of the clue.
How the clue works
Restive is your definition — anxious, fidgety, can't settle. Then it's a straightforward build: UN meaning "not" tagged onto EASY meaning "simple", with "so" just acting as a bridge between the wordplay and the definition.