Officer's hair alarms criminal (3,7)
I believe the answer is:
air marshal
'officer's' is the definition.
Both the answer and definition are singular nouns.
Maybe they are linked in a way I don't understand?
'hair alarms criminal' is the wordplay.
'criminal' is an anagram indicator.
'hair'+'alarms'='hairalarms'
'hairalarms' with letters rearranged gives 'AIR-MARSHAL'.
Can you help me to learn more?
(Other definitions for air marshal that I've seen before include "RAF officer" , "Senior air force officer" .)