He's learned to show a cold heart in a terrible crash (7)
I believe the answer is:
scholar
'he's learned to' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'a cold heart in a terrible crash' is the wordplay.
'heart' means to look at the middle letters.
'in' is an insertion indicator.
'a terrible' indicates an anagram.
The centre of 'cold' is 'ol'.
'crash' anagrammed gives 'schar'.
'ol' put within 'schar' is 'SCHOLAR'.
'show' is the link.
Can you help me to learn more?
(Other definitions for scholar that I've seen before include "Pupil - erudite person" , "Person of learning" , "university type?" , "Learned type" , "Noted academic" .)