Old lady cheers a couple of home guards for support (8)
I believe the answer is:
maintain
'support' is the definition.
(thesaurus)
'old lady cheers a couple of home guards' is the wordplay.
'old lady' becomes 'ma'.
'cheers' becomes 'ta' (I've seen this in other clues**).
'a couple of' indicates the doubling of some letters.
'home' becomes 'in' ('he's home' can mean 'he's in').
'guards' indicates putting letters inside.
'in' duplicated is 'inin'.
'ta' inserted into 'inin' is 'intain'.
'ma'+'intain'='MAINTAIN'
'for' is the link.
(Other definitions for maintain that I've seen before include "Preserve or insist" , "Conserve" , "Look after the upkeep" , "Keep (a building) in good condition" , "Keep going" .)