One not still searching for hobby? (8)
I believe the answer is:
twitcher
I believe this clue is a double definition.
'one not still' is the first definition.
(someone who isn't still)
'searching for hobby?' is the second definition.
(a hobby is a bird - a twitcher is a birdwatcher)
(Other definitions for twitcher that I've seen before include "Spasmodic" , "Measure; creep" , "One not still" , "Name for a keen bird-watcher" , "Rare bird spotter" .)