I retain unusual state of inactivity (7)
I believe the answer is:
inertia
'state of inactivity' is the definition.
'inertia' can be an answer for 'inactivity' (I've seen this before). I am not sure about the 'state of' bit.
'i retain unusual' is the wordplay.
'unusual' indicates anagramming the letters.
'retain' with letters rearranged gives 'nertia'.
'i'+'nertia'='INERTIA'
Can you help me to learn more?
(Other definitions for inertia that I've seen before include "Slowness to act, lack of strength" , "Disposition to do nothing" , "Reluctance to change" , "I retain (anag) - the tendency to retain same speed and direction" , "Listlessness" .)