Block entrance to conservatory during Cluedo unfortunately (7)
I believe the answer is:
occlude
'block' is the definition.
(I know that block can be written as occlude)
'entrance to conservatory during cluedo unfortunately' is the wordplay.
'entrance to' indicates taking the first letters.
'during' indicates putting letters inside.
'unfortunately' indicates anagramming the letters (a bad or unfortunate spelling).
The initial letter of 'conservatory' is 'c'.
'cluedo' anagrammed gives 'oclude'.
'c' placed within 'oclude' is 'OCCLUDE'.
(Other definitions for occlude that I've seen before include "Close up (an orifice or passage)" , "Shut out, obscure" , "Cod clue to shut out" , "cover" , "Stop up, obstruct" .)