Complain, asking why regularly (4)
I believe the answer is:
sigh
'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.).
'asking'+'why'='askingwhy'
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" .)