Or search: plus, lucky, plausive, approving, expedient, indulgent, opportune, beneficial, profitable, propitious, prosperous, favourable, affirmative, affirmatory, approbatory
3 Syllables: SUU
admirable, capable, miserable, payable, preferable, traceable
4 Syllables: SUUU
answerable, favourable, honorable, honourable, measurable, memorable, pleasurable, separable, tolerable, venerable, vulnerable
4 Syllables: USUU
attainable, available, debatable, desirable, discoverable, incapable, insatiable, obtainable, occasional, relational, rotational, sensational, transferable, unshakable, vocational
5 Syllables: USUUU
considerable, dishonorable, dishonourable, incomparable, inexorable, innumerable, inseparable, insufferable, insuperable, intolerable, invulnerable, irreparable, recoverable, unalterable, unanswerable, unconquerable, unfavorable, unfavourable, unutterable
5 Syllables: UUSUU
ascertainable, computational, Congregational, conversational, educational, gravitational, inescapable, inspirational, observational, occupational, operational, recreational, situational, unassailable, unattainable, unavailable, undesirable, unmistakable
6 Syllables: UUSUUU
inconsiderable, unendurable
6 Syllables: UUUSUU
denominational, organizational

Found 73 words across 7 groupings.