More painful part of stomach, i.e. reticulum (6)

I believe the answer is:

achier

'more painful' is the definition.
('achy' can be similar in meaning to 'painful')

'part of stomach i e reticulum' is the wordplay.
'part of' says the answer is hidden in the clue.
'ACHIER' is hidden within 'stomach i e reticulum'.

(Another definition for achier that I've seen is " Feeling more pain".)

I've seen this clue in The Everyman puzzle in The Observer.

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