Getting on is something to shout about, mate (5)
I believe the answer is:
crony
'mate' is the definition.
(I've seen this before)
'getting on is something to shout' is the wordplay.
I cannot quite understand how this works, but
'on' is found in the answer.
'shout' could be 'cry' (synonyms) and 'cry' is present in the leftover letters.
No letters remain.
This explanation may well be incorrect...
'about' acts as a link.
Can you help me to learn more?
(Other definitions for crony that I've seen before include "China" , "Intimate companion" , "Corny (anag.)" , "Sidekick" , "mate" .)