Tender payment in support of secretary (8)
I believe the answer is:
parental
'tender' is the definition.
(thesaurus)
'payment in support of secretary' is the wordplay.
'payment' becomes 'rental' (I've seen this before).
'in support of' says to put letters next to each other (in a down clue, some letters hold up others).
'secretary' becomes 'PA' (abbreviation for personal assistant).
'rental' put after 'pa' is 'PARENTAL'.
(Other definitions for parental that I've seen before include "of some older relatives" , "Of mother and/or father" , "of old man and woman" , "like mum and dad" , "Relating to mother and father" .)