Look out! There's a battle in the bee house (6)
I believe the answer is:
beware
'look out' is the definition.
(bewaring is a kind of looking out)
'a battle in the bee house' is the wordplay.
'a battle' becomes 'war' (armed conflict).
'in' is an insertion indicator.
'the bee' becomes 'b'.
'house' becomes 'ee' (I am not sure about this - if you are sure you should believe this answer much more).
'b'+'ee'='bee'
'war' put within 'bee' is 'BEWARE'.
'there's' is the link.
Can you help me to learn more?
(Other definitions for beware that I've seen before include "Be alert for dangers" , "Word of warning" , "Steer clear of" , "Have caution, be on guard" , "Look out, danger ahead" .)