Functioning rhymes with:
malfunctioning, malfunctioning, malfunctioning, sanctioning, auctioning, malfunctioning, sanctioning, sectioning, airconditioning, apportioning, auctioning, auditioning, captioning, cautioning, commissioning, conditioning, cushioning, decommissioning, fashioning, freshening, malfunctioning, mentioning, motioning, optioning, partitioning, petitioning, positioning, rationing, reconditioning, repositioning, sanctioning, sectioning, stationing, transitioning, vacationing
Functioning sounds like:
feinstein's, fumigating, functions