Complex structure allowed two males to snare a freshie overseas (9)
I believe the answer is:
macrocosm
'complex structure allowed two' is the definition.
I can't tell whether this definition defines the answer.
'males to snare a freshie overseas' is the wordplay.
'males' becomes 'mm' (an abbreviation for male written twice).
'to snare' is an insertion indicator (inserted letters are trapped or snared).
'freshie' becomes 'croc' (I can't justify this - if you can you should give a lot more credence to this answer).
'overseas' becomes 'os' (abbreviation).
'a'+'croc'+'os'='acrocos'
'mm' enclosing 'acrocos' is 'MACROCOSM'.
Can you help me to learn more?
(Another definition for macrocosm that I've seen is " The universe, or any great whole".)