the hand that feeds one
Bitten by (some kind of) bug
Bitter pill to swallow
Black and blue
Black and white
Black box
Black eye
Black market
Black out
Black sheep of the family
Black-tie event/affair
Blackball (someone)
Blacklist (someone)
Blackmail (someone)
Blackout
Blast off
Blaze a trail (in something)
Bleeding heart
Bleep (something) out
Blessing in disguise
Blind date
Blind leading the blind
Blood is thicker than water
Blood runs cold
Blood, sweat, and tears
Blow (someone or something) off
Blow (someone's) cover
Blow (someone's) mind
Blow (someone) away
Blow (something)
Blow (something) out of all proportion
Blow a fuse
Blow one's nose
Blow one's own horn
Blow one's stack/top
Blow one's top/stack
Blow over
Blow the lid off (something)
Blow the whistle on someone
Blow to smithereens
Blow up (at someone)
Blow up in (someone's) face
BLT
Blue blood
Blue in the face
Blue-ribbon
BO
Body blow
Bog down
Boggle one's mind
Boil down to (something)
Bona fide
Bone of contention
Bone up (on something)
Bonehead
Booked solid
Bookworm
Boot out
Bore (someone) stiff/to death
Bored out of one's mind/skull
Born out of wedlock
Born with a silver spoon in one's mouth
Bosom friend
Boss (someone) around
Bottle (something) up
Bottom dollar
Bottom drops/falls out of (something)
Bottom line
Bottom out
Bottoms up!
Bounce a check
Bounce something (an idea) off someone
Bound and determined
Bound for somewhere
Bound hand and foot
Bound to (do something)
Bow and scrape
Bow out
Bowl (someone) over
Boys in the backroom
Brain (someone)
Brain drain
Brain teaser
Brainchild
Brainless
Brains behind (something)
Brainstorm something
Brainwash (someone)
Brand-new
Breach of promise
Breach of the peace
Bread and butter
Bread and water
Break (someone's) fall
Break (someone's) heart
Break (something) down
Break (something) to (someone)
Break a habit
Break a law
Break a leg!
Break a record
Break camp
Break down
Break down (something)
Break even
Break fresh/new ground
Break ground for (something)
Break in (someone or something)
Break into a cold sweat (about something)
Break into tears
Break loose (from someone or something)
Break off
Break one's back/neck (to do something)
Break one's word
Break out in (something)
Break out in a cold sweat
