It's appropriate to have one American brought back on board (8)
I believe the answer is:
suitable
'it's appropriate' is the definition.
(similar in meaning)
'one american brought back on board' is the wordplay.
'one' becomes 'i' (Roman numeral).
'american' becomes 'US' (United States).
'brought back' says the letters should be written backwards.
'on' says to put letters next to each other (in a down clue, letters appear on others).
'board' becomes 'table' (both can mean food).
'i'+'us'='ius'
'ius' back-to-front is 'sui'.
'sui'+'table'='SUITABLE'
'to have' acts as a link.
(Other definitions for suitable that I've seen before include "Satisfactory, worthy" , "Convenient" , "Appropriate, fitting" , "Appropriate, meet" , "Becoming" .)