Equal parts stiff and hot after exercising (6)
I believe the answer is:
fifths
'equal parts' is the definition.
The answer and definition can be both related to communication as well as being plural nouns.
Perhaps there's a link between them I don't understand?
'stiff and hot after exercising' is the wordplay.
'and' says to put letters next to each other.
'hot' becomes 'h' (abbreviation eg on taps).
'after exercising' indicates an anagram.
'stiff'+'h'='stiffh'
'stiffh' with letters rearranged gives 'FIFTHS'.
Can you help me to learn more?
(Other definitions for fifths that I've seen before include "... of these for 60%" , "Fractions" .)