Blank college head gets new pad (7)
I believe the answer is:
deadpan
'blank' is the definition.
(I've seen this before)
'college head gets new pad' is the wordplay.
'college head' becomes 'dean' (I've seen this in another clue).
'gets' means one lot of letters goes inside another (gets can mean captures or absorbs).
'new' is an anagram indicator.
'pad' anagrammed gives 'adp'.
'dean' going around 'adp' is 'DEADPAN'.
(Other definitions for deadpan that I've seen before include "Dry" , "Impassive" , "Poker-faced" , "Not giving anything away" , "Betraying no emotion" .)