Press for outrigger to be used regularly (4)
I believe the answer is:
urge
'press for' is the definition.
(I've seen this in another clue)
'outrigger to be used regularly' is the wordplay.
'to be used regularly' indicates alternate letters.
The alternate letters of 'outrigger' are 'URGE'.
(Other definitions for urge that I've seen before include "Sudden desire" , "Encourage to proceed, drive onwards" , "Strongly recommend; impulse" , "Itch" , "Advise earnestly, spur" .)