easy, soft, weak, limp
hard
hard
Toil.
cash
The four letter word for stern as a noun : Rear to mean rear of a ship or aircraft.The four letter word for stern as an adjective: Hard to mean strict.
HARD
hare
Hard, hare, hark, harm, harp, hart.
Rock.
A four letter word starting with the letter a is able.
Echo
It depends on what you mean by 'four letter word'. Thea has four letters, so yes it is. It is not a swear word, so it's not that kind of 'four letter word'.