He gets publicity for principals (5)
I believe the answer is:
heads
'for principals' is the definition.
('head' can be a synonym of 'principal')
'he gets publicity' is the wordplay.
'gets' says to put letters next to each other.
'publicity' becomes 'ads' (advert).
'he'+'ads'='HEADS'
(Other definitions for heads that I've seen before include "Goes for" , "Noddles; nuts" , "Coin-tossing call" , "Leaders" , "School principals" .)