Some freckles, spots or rash (8)
I believe the answer is:
reckless
'rash' is the definition.
(rash can mean impulsive or thoughtless)
'some freckles spots or' is the wordplay.
'some' indicates the answer is hidden within the clue (some parts of the word are used).
'RECKLESS' is hidden within 'freckles spots or'.
(Other definitions for reckless that I've seen before include "Devil-may-care" , "Careless, rash" , "Irresponsible" , "not responsible" , "Without thought for the consequences" .)