caught between two stools
clash
disagree
misdifferentiate
incompatible
nonconformance
unsuited
unassimilating
underdiversify
nonconvergence
misfire
inconsistent
ill-matched
unconvergence
fall between two stools
uncomparable
misfit
come short
have it both ways
incompossible
fall short
go nowhere fast
unadvancement
nonattainment
between two stools
nondiversification
mispair
nonfulfilment
nondifferentiation
oil and water
unassimilability
incomparable
disappoint
noncompetency
uncompatible
let down
bad
hippie
die in the ass
go nowhere
unclassifiable
noncombinative
neither fish nor fowl
unmatchable
self-defeating
omit
unduplicability
criterionlessness
non-replicable
let go
nondiversifiable
nonqualifier
leave a lot to be desired
undiversifiable
unevaluatable
irreplicable
malfunction
anorchidism
anorchism
anorchia
unhomogeneity
miss the mark
unable
fumblingness
incomparability
unqualifiable
divergenceless
nonstandardization
apples and oranges
miss
die on the vine
underdog
second best
inevaluable
failure
misharmonized
futile
unappliable
unsteady
dissimilarity
nonidentity
unresolving
disconformable
mischeck
incorrespondence
ungroupable
ill-suited
nondifference
nonconformable
mismatching
ununiting
mismatch
fail
unconformity
unconformable
unsuccess
mismatchment