They're not about to disturb a bees' nest (9)
I believe the answer is:
absentees
'they're not' is the definition.
The definition suggests an adverb but the answer is not.
'to disturb a bees' nest' is the wordplay.
'to disturb' indicates anagramming the letters (I've seen 'disturbed' mean this (the order of letters is disturbed)).
'a'+'bees'+'nest'='abeesnest'
'abeesnest' with letters rearranged gives 'ABSENTEES'.
'about' is the link.
Can you help me to learn more?
(Other definitions for absentees that I've seen before include "who may have apologised to chairman" , "One gets fonder of those" , "They're not present at the required time" .)