Being underground makes men go wild (5)
I believe the answer is:
gnome
'being underground' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
'men go wild' is the wordplay.
'wild' is an anagram indicator.
'men'+'go'='mengo'
'mengo' with letters rearranged gives 'GNOME'.
'makes' acts as a link.
Can you help me to learn more?
(Other definitions for gnome that I've seen before include "Little old man of legend" , "Mythical sprite" , "Figure of sinister influence" , "Small fellow" , "Underground dwarf" .)