Five out of seven will be spotted (4)
I believe the answer is:
seen
'spotted' is the definition.
(I've seen this in other clues)
'five out of seven' is the wordplay.
'five' becomes 'v' (roman numeral).
'out of' suggests deleting specific letters.
'seven' with 'v' removed is 'SEEN'.
'will be' acts as a link.
(Other definitions for seen that I've seen before include "Witnessed" , "Spotted" , "Espied" , "Met - understood" , "Sighted" .)