Obstinate old president swallows brought up sick (7)
I believe the answer is:
bullish
'obstinate old' is the definition.
Both the definition and answer are adjectives. Perhaps you can see a link between them that I don't see?
'president swallows brought up sick' is the wordplay.
'president' becomes 'bush' (George H W Bush or George W Bush).
'swallows' is an insertion indicator.
'brought up' says the letters should be written backwards (in a down clue, letters go up).
'sick' becomes 'ill' (synonyms).
'ill' in reverse letter order is 'lli'.
'bush' placed around 'lli' is 'BULLISH'.
Can you help me to learn more?
(Another definition for bullish that I've seen is " Confident".)