bail
fall back
undercommit
welch
renege
renegue on
go back on
renege on
miss
miscarry
fainaigue
miss the mark
go nowhere
mismeet
forfeit
underachieve
spoil the ship for a ha'p'orth of tar
default
neglect
omit
strike out looking
promise the moon
drop the ball
mispledge
bite the big one
die on the vine
leave someone out in the cold
scantle
under-accommodate
bottle out
founder
go over like a lead balloon
leave someone cold
nonconform
retract
push one's luck
wither on the vine
go down in flames
flake
repine
disobey
require improvement
write checks one can't cash
not win for losing
missuit
hit the skids
fall flat on one's face
self-handicap
languish
break