2 Syllables: SU
brightening, cycling, firing, frightening, heightening, hiring, idling, ripening, stifling, tightening, tiring, wiring
3 Syllables: SUU
biases, dualism, hyacinth, lightening, nihilism, quieting, rioting, viruses, widening
3 Syllables: USU
acquiring, admiring, aspiring, conspiring, desiring, enquiring, entitling, expiring, inquiring, inspiring, perspiring, requiring, retiring
4 Syllables: SUUU
dynamism, fatalism, federalism, feudalism, formalism, journalism, naturalism, pluralism, socialism, symbolism, vandalism
4 Syllables: USUU
deciphering, disquieting, enlightening, enlivening
5 Syllables: USUUU
colonialism, imperialism, industrialism, materialism, metabolism, paternalism, provincialism
6 Syllables: UUSUUU
sentimentalism
6 Syllables: UUUSUU
individualism

Found 58 words across 8 groupings.