Help Matilda every now and again (3)
I believe the answer is:
aid
'help' is the definition.
('aid' can be a synonym of 'help')
'matilda every now and again' is the wordplay.
'every now and again' indicates alternate letters.
The alternate letters of 'matilda' are 'AID'.
(Other definitions for aid that I've seen before include "charity" , "welfare" , "Care, assistance" , "Relief" , "technique that can produce pregnancy" .)