Or search: obnoxious, offensive, unacceptable, exceptionable
3 Syllables: SUU
fashionable, reasonable
4 Syllables: SUUU
pardonable, questionable, reputable, seasonable, treasonable
5 Syllables: USUUU
abominable, companionable, determinable, disreputable, imaginable, impressionable, inalienable, inexorable, interminable, unfashionable, unpardonable, unquestionable, unseasonable
6 Syllables: UUSUUU
unexceptionable

Found 21 words across 4 groupings.