Discourage from going into lakeside territory (5)
I believe the answer is:
deter
'discourage' is the definition.
(I know that discourage can be written as deter)
'going into lakeside territory' is the wordplay.
'going into' says the answer is hidden in the clue.
'DETER' can be found hidden inside 'lakeside territory'.
'from' is the link.
(Other definitions for deter that I've seen before include "Dishearten" , "Discourage (someone from an action)" , "Discourage through fear of consequences" , "Frighten off; prevent" , "Discourage or impede" .)