They get heated when there's a toss up! (5)
I believe the answer is:
oasts
'they get heated' is the definition.
The definition suggests an adverb but the answer is not.
'there's a toss up' is the wordplay.
'there's' says to put letters next to each other.
'up' is an anagram indicator (letters get chucked up).
'a' put next to 'toss' is 'atoss'.
'atoss' is an anagram of 'OASTS'.
'when' acts as a link.
Can you help me to learn more?
(Other definitions for oasts that I've seen before include "Houses" , "Malt dryers" , "Kilns for drying hops" .)