back – in front of
background – foreground
backward – forward
bad – good
bad luck – fortune
beauty – ugliness
before – after
begin – end
beginning – end
behind – in front of
below – above
best – worst
better – worse
beautiful – ugly
big – small
birth – death

bitter – sweet
black – white
blunt – sharp
body – soul
bore – amuse
boring – exciting
borrow – lend
bottom – top
boy – girl
brave – cowardly
break – fix
broad – narrow
brother – sister
build – destroy
busy – lazy
buy – sell