Yeoman’s ale containing iron consumed (9)
I believe the answer is:
beefeater
'yeoman's' is the definition.
(synonyms)
'ale containing iron consumed' is the wordplay.
'ale' becomes 'beer' (I've seen this in other clues).
'containing' means one lot of letters goes inside another.
'iron' becomes 'Fe' (Fe is the chemical symbol for iron).
'consumed' becomes 'ate' (to eat is to consume food).
'fe'+'ate'='feate'
'beer' enclosing 'feate' is 'BEEFEATER'.
(Other definitions for beefeater that I've seen before include "Bodyguard of the British monarch" , "no vegetarian?" , "Yeoman warder of the Tower of London" , "One might guard" , "Tower of London guard" .)