Here's what rhymes with lightweightness.
lateness greatness straightness elaborateness deliberateness Words that almost rhyme with lightweightness
waitress weightless heinous sameness faintness plainness quaintness tameness basis famous nameless platelets blameless faithless hiatus painless shameless tasteless baseless faceless grayness greyness tailless patience gracious courageous spacious stainless cadence outrageous tenacious valence audacious herbaceous shapeless strangeness bailiffs fracas graceless loquacious profaneness patients acquaintance payments fragrance abeyance capacious fallacious sebaceous vivacious voracious vagrants flirtatious salacious humaneness intranets arrangements statements impatience surveillance attainments claimants contagious efficacious reagents assailants pavements placements vexatious basements mandamus repayments ungracious ignoramus mendacious periphrasis advantageous conveyance replacements ostentatious complainants complaisance inpatients complacence farinaceous inhalants perspicacious engagements entertainments rearrangements emplacements misstatements disputatious displacements homeostasis disadvantageous