There are 414 4-letter words containing B in the ENABLE dictionary — 11% of all 3,903 words at this length. B is a one-point tile, so the value in this list is positional rather than numerical — which of these you can play depends far more on where it fits the board than on what it scores.
The B falls in the first position more often than any other, in 251 of them. 23 of them use the letter more than once — abba, abbe, baba, babe among them, which is the case worth checking twice when a game has told you a letter is present but not how many times.
If you know more than one letter, this page stops being the fast way to find it. Enter what you have in the unscrambler — the Contains, Starts with and Ends with filters combine, and setting both length fields to 4 narrows this list to the handful your letters actually allow.
Where the B sits
B in the first position (251)
baal baas baba babe babu baby bach back bade bads baff bags baht bail bait bake bald bale balk ball balm bals bams band bane bang bani bank bans baps barb bard bare barf bark barm barn bars base bash bask bass bast bate bath bats batt baud bawd bawl bays bead beak beam bean bear beat beau beck beds bedu beef been beep beer bees beet begs bell bels belt bema bend bene bens bent berg berm best beta beth bets bevy beys bhut bias bibb bibs bice bide bids bier biff bigs bike bile bilk bill bima bind bine bins bint bios bird birk birl birr bise bisk bite bits bitt bize blab blae blah blam blat blaw bleb bled blet blew blin blip blob bloc blot blow blub blue blur boar boas boat bobs bock bode bods body boff bogs bogy boil bola bold bole boll bolo bolt bomb bond bone bong bonk bony boob book boom boon boor boos boot bops bora bore born bort bosh bosk boss bota both bots bott bout bowl bows boxy boyo boys bozo brad brae brag bran bras brat braw bray bred bree bren brew brie brig brim brin brio bris brit broo bros brow brrr brut bubo bubs buck buds buff bugs buhl buhr bulb bulk bull bumf bump bums bund bung bunk bunn buns bunt buoy bura burd burg burl burn burp burr burs bury bush busk buss bust busy bute buts butt buys buzz byes byre byrl byte
B in the second position (24)
abas abba abbe abed abet able ably abos abri abut abye abys ebbs ebon ibex ibis kbar obes obey obia obis obit oboe obol