What might irritate some smaller gentlemen (8)
I believe the answer is:
allergen
'what might irritate' is the definition.
I can't tell whether this defines the answer.
'some smaller gentlemen' is the wordplay.
'some' indicates the answer is hidden within the clue (some of the parts of the word are used).
'ALLERGEN' can be found hidden inside 'smaller gentlemen'.
Can you help me to learn more?
(Other definitions for allergen that I've seen before include "One provokes a reaction" , "Substance triggering an abnormal bodily reaction" , "that may produce adverse reaction" , "Protein" , "Wheat, say" .)