The jungly mass one cleaves? (7)
I believe the answer is:
machete
'the jungly mass one cleaves?' is the definition.
I can't judge whether this definition defines the answer.
'the jungly mass one' is the wordplay.
I cannot quite see how this works, but
an anagram of 'the' is 'het' which is within the answer.
'mass' could be 'm' (symbol used in Physics e.g. f=ma) and 'm' is present in the answer.
'one' could be 'ace' (ace has a value of one in some card games) and 'ace' is located in the leftover letters.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for machete that I've seen before include "Teach me with large jungle knife" , "cutter" , "Heavy knife used as weapon" , "Broad heavy knife common in Central America" , "A heavy-duty jungle knife" .)