The rod may become overheated (3,3)
I believe the answer is:
red hot
'overheated' is the definition.
(thesaurus)
'the rod may become' is the wordplay.
'may become' indicates an anagram.
'the'+'rod'='therod'
'therod' anagrammed gives 'RED-HOT'.
(Other definitions for red hot that I've seen before include "Extremely exciting" , "Sizzling" , "Burning" , "Very keen" , "Fiercely glowing" .)