Digit displayed by student, humble (5)
I believe the answer is:
thumb
'digit' is the definition.
(I know that thumb is a type of Finger)
'displayed by student humble' is the wordplay.
'displayed by' indicates the answer is hidden within the clue.
'THUMB' can be found hidden inside 'student humble'.
(Other definitions for thumb that I've seen before include "Try to get a lift" , "Big digit" , "Attempt to obtain a lift" , "Travel by getting free rides from motorists" , "Tom, for example" .)