"glad"
felt
appreciate
appreciate
grateful
A four letter word starting with the letter a is able.
Fell, tell the, feel, hi, felt, ill
feet, feat, fear, felt, fest, feed, feel, fete, fern, fees, fens
The comparative form of "grateful" is "more grateful".
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'.
A four letter word for 'in addition to' is also.
That Four-Letter Word was created in 2006.
Lard is a four letter word for grease.