Proofing rhymes with:
rustproofing, roofing, rustproofing, goofing, roofing, rustproofing, spoofing, beefing, bluffing, briefing, chafing, choreographing, coffing, coughing, debriefing, doffing, dwarfing, engulfing, fireproofing, golfing, goofing, griffing, handcuffing, huffing, knifing, laughing, leafing, morphing, offing, photographing, puffing, rebuffing, riffing, rohlfing, roofing, roughing, ruffing, rustproofing, safing, sniffing, snuffing, spiffing, spoofing, staffing, strafing, stuffing, surfing, waterproofing
Proofing sounds like:
parfums, perfumes, perfuming, peruvians, pervomaiskaya, prepaying, prepping, previewing, probing, propionic, propping, provance, provenance, provence, provencio, provenience, provenza, province, province's, provinces, proving, purifying, purveying, purviance