Behold very large European general (5)
I believe the answer is:
loose
'general' is the definition.
(synonyms)
'behold very large european' is the wordplay.
'behold' becomes 'lo' ('lo' is an archaic exclamation meaning 'look!').
'very large' becomes 'os' (abbreviation for oversize).
'european' becomes 'E' (abbreviation e.g. EU).
'lo'+'os'+'e'='LOOSE'
(Other definitions for loose that I've seen before include "Not tightly fixed" , "Vague -- insecure" , "Liberal" , "Promiscuous" , "Not secured" .)