First-year student cheeky in front of staff (8)
I believe the answer is:
freshman
'first-year student' is the definition.
(I've seen this before)
'cheeky in front of staff' is the wordplay.
'cheeky' becomes 'fresh' (I've seen this before).
'in front of' is a charade indicator (letters next to each other).
'staff' becomes 'man' (manning is a kind of staffing).
'fresh'+'man'='FRESHMAN'
(Other definitions for freshman that I've seen before include "He's a first-year college student" , "New male student" , "Student in his first year" , "newly experiencing life in Jesus?" , "Young person" .)