A loaf.
A four letter word starting with the letter a is able.
loaf
MakeMindMineMastMassMustMeatMeetMinkMireMadeMaidMazeMoreMood
poet
urge
ecru
A four letter word starting with J is jump or joke.
Ham.
Merl
kook
Kick
Four letter words starting with B and ending with W are blew, blow, brow, and brew.