Reminder to inject testosterone, dear (4)
I believe the answer is:
cute
'dear' is the definition.
Both the answer and definition are adjectives. Perhaps you can see a link between them that I can't see?
'reminder to inject testosterone' is the wordplay.
'reminder' becomes 'cue' (eg a cue for an actor on stage).
'to inject' means one lot of letters goes inside another (inserted letters are injected).
'testosterone' becomes 't' (this could be a standard abbreviation I've not previously seen).
'cue' enclosing 't' is 'CUTE'.
Can you help me to learn more?
(Other definitions for cute that I've seen before include "Appealing -- cunning" , "winning" , "Endearing" , "Fly" , "Taking" .)