He perhaps gets spattered with rain (5,3)
I believe the answer is:
inert gas
'he perhaps' is the definition.
(helium - symbol 'He' - is an example)
'gets spattered with rain' is the wordplay.
'spattered with' is an anagram indicator.
'gets' anagrammed with 'rain' can make 'INERT GAS'.
(Other definitions for inert gas that I've seen before include "He perhaps" , "provokes no reaction" , "Eg, helium, xenon etc." , "Eg, helium or argon" , "Such as neon or xenon" .)