BIFACE
BIFACES
BIFACIAL
BIFACIALLY
BIFARIOUS
BIFARIOUSLY
BIFF
BIFFED
BIFFER
BIFFERS
BIFFIES
BIFFIN
BIFFING
BIFFINS
BIFFO
BIFFOS
BIFFS
BIFFY
BIFID
BIFIDITIES
BIFIDITY
BIFIDLY
BIFILAR
BIFILARLY
BIFLAGELLATE
BIFLEX
BIFOCAL
BIFOCALED
BIFOCALS
BIFOLD
BIFOLIATE
BIFOLIOLATE
BIFORATE
BIFORKED
BIFORM
BIFORMED
BIFTER
BIFTERS
BIFUNCTIONAL
BIFURCATE
BIFURCATED
BIFURCATES
BIFURCATING
BIFURCATION
BIFURCATIONS

45 words start with BIF.