Terribly mean, telephoning insults (4-7)

I believe the answer is:

name-calling

I'm a little stuck... Click here to teach me more about this clue!

'terribly mean telephoning insults' is the definition.
I can't tell whether this definition defines the answer.

'terribly mean telephoning' is the wordplay.
'terribly' indicates anagramming the letters.
'telephoning' becomes 'calling' ('call' can be a synonym of 'telephone').
'mean' anagrammed gives 'name'.
'name'+'calling'='NAME-CALLING'

Can you help me to learn more?

(Another definition for name-calling that I've seen is " Verbal abuse".)

I've seen this clue in The Mirror.

Want a hint initially instead of a full solution? Install my app