Contemptible when in a rash? (6)
I believe the answer is:
measly
'contemptible' is the definition.
(thesaurus)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for measly that I've seen before include "not at all generous" , "'Contemptibly small, paltry (6)'" , "ungenerous in amount" , "Spotted in bed, perhaps" , "Ridiculously small" .)