Or search: mime, mock, sham, feign, feint, mimic, imitate, pretend, dissemble, reproduce
2 Syllables: SU
interests
3 Syllables: SUU
inculcate, indicate, infinite, integrate, intimate, intricate, invalid, stimulate, syndicate, vindicate
4 Syllables: USUU
assimilate, disintegrate

Found 13 words across 3 groupings. Skipped 4 excess words of a similar stem.