Eyeshade? Guest has dropped it (5)
I believe the answer is:
visor
'eyeshade?' is the definition.
('visor' can be a synonym of 'eyeshade')
'guest has dropped it' is the wordplay.
'guest' becomes 'visitor' (I've seen this before).
'has dropped' suggests deleting specific letters.
'visitor' with 'it' taken away is 'VISOR'.
(Other definitions for visor that I've seen before include "One protecting" , "Eyeshade" , "Screen to filter glare" , "Face guard; sun screen" , "Movable front part of helmet" .)