Some people know where grouse display
I believe the answer is:
lek
'grouse display' is the definition.
Although both the answer and definition are singular nouns, I cannot see how one could define the other.
'some people know where' is the wordplay.
'some' indicates a hidden word (some of the parts of the word are used).
'LEK' can be found hidden inside 'people know where'.
Can you help me to learn more?
(Other definitions for lek that I've seen before include "area with more than a single grouse" , "Display of birds here" , "change in the Balkans" , "Monetary unit of Albania" , "Display ground" .)