Keep performers at edge of lake (6)
I believe the answer is:
castle
'keep' is the definition.
(I've seen this before)
'performers at edge of lake' is the wordplay.
'performers' becomes 'cast' (I've seen this before).
'at' says to put letters next to each other.
'edge of' says to hollow out the word (remove centre letters) (I've seen 'edges of' mean this).
'lake' with its middle removed is 'le'.
'cast'+'le'='CASTLE'
(Other definitions for castle that I've seen before include "Chateau" , "ancient building?" , "splendid house" , "Stately home in Yorkshire" , "Large fortified building" .)