Complain, asking why regularly (4)
I believe the answer is:
'complain' is the definition.
The definition and answer can be both to do with communicating as well as being verbs in their base form.
Perhaps they are linked in a way I don't understand?
'asking why regularly' is the wordplay.
'regularly' indicates alternate letters (regularly take one letter, leave next etc.).
The alternating letters of 'askingwhy' are 'SIGH'.
Can you help me to learn more?
(Other definitions for sigh that I've seen before include "Sound of despondency" , "Moan softly" , "Sad-sounding exhalation" , "Release a long breath" , "Vocal expression of weariness" .)