Person regularly paid worker (3)
I believe the answer is:
pro
'paid worker' is the definition.
(I've seen this before)
'person regularly' is the wordplay.
'regularly' indicates alternate letters (regularly take one letter, leave next etc.).
The alternating letters of 'person' are 'PRO'.
(Other definitions for pro that I've seen before include "Competent person" , "gets paid to play?" , "In short, not an amateur" , "Preposition meaning for, in favour of" , "hooker" .)