Unusually attentive but hesitant (9)
I believe the answer is:
tentative
'hesitant' is the definition.
(I've seen this before)
'unusually attentive' is the wordplay.
'unusually' is an anagram indicator.
'attentive' anagrammed gives 'TENTATIVE'.
'but' acts as a link.
(Other definitions for tentative that I've seen before include "Exploratory - hesitant" , "Experimental" , "Conjectural" , "Exploratory, unconfident" , "Attentive in hesitant manner" .)