I retain strange apathy (7)

I believe the answer is:

inertia

'apathy' is the definition.
(I've seen this before)

'i retain strange' is the wordplay.
'strange' is an anagram indicator.
'retain' is an anagram of 'nertia'.
'i'+'nertia'='INERTIA'

(Other definitions for inertia that I've seen before include "Slowness to act, lack of strength" , "Lack of inclination to move" , "Apathy" , "Motion (if any) when no external force is applied" , "Tendency to inactivity" .)

I've seen this clue in The Guardian.

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