Interfirst rhymes with:
first, furst, guaranty-first, headfirst, medfirst, berst, burst, coerced, conversed, cursed, disbursed, dispersed, durst, emersed, first, furst, gerst, guaranty-first, headfirst, hearst, herst, hirst, huerst, hurst, immersed, interspersed, kerst, kirst, medfirst, merced, nursed, pursed, rehearsed, reimbursed, reversed, submersed, thirst, unrehearsed, unreimbursed, versed, werst, worst, wurst