The same change can be make to the two regular words and the two informal ones below to get four new words. What is the change and what are the new words?

CHING

WING

GENT

TAC 

 

HINT:

1. Venus de Milo feature

 

Answer:

 

The letters/word ARM can be inserted in each word to make a new one:

 

CHARMING

WARMING

GARMENT

TARMAC 

Credit:
Brendan Emmett Quigley