Suggest convict holds appeal up (8)
I believe the answer is:
intimate
'suggest' is the definition.
(intimating is a kind of suggesting)
'convict holds appeal up' is the wordplay.
'convict' becomes 'inmate' (synonyms).
'holds' indicates putting letters inside.
'appeal' becomes 'it' ('it' can mean something attractive or appealing).
'up' says the letters should be written in reverse (in down clue: letters go upwards).
'it' reversed gives 'ti'.
'inmate' going around 'ti' is 'INTIMATE'.
(Other definitions for intimate that I've seen before include "Personal - hint - friend" , "Familiar; imply" , "Close acquaintance" , "cosy" , "Make known" .)