Synonyms to hard as nails

cement, Tarmac, Tarvia, accouple, accumulate, adamant, adhere, adherent, adhesive, adobe, affix, agglutinate, amass, anchor, annex, articulate, ashlar, asphalt, assemble, associate, attach, band, barnacle, belay, bind, biscuit, bisque, bitumen, bituminous macadam, blacktop, bond, bone, bony, bowl, bracket, bramble, braze, brick, bricks and mortar, bridge, bridge over, brier, bulldog, burr, carpet, causeway, cemental, ceramic ware, ceramics, chain, china, cinch, clamp, clap together, clinch, cling, clinker, cobble, cobblestone, cohere, collect, combine, comprise, concatenate, concrete, conglobulate, conjoin, conjugate, connect, copulate, corneous, couple, cover, covering materials, cramp, crock, crockery, curb, curbing, curbstone, decal, decalcomania, dense, diamond, diamondlike, dure, edgestone, embrace, enamelware, encompass, engraft, fasten, ferroconcrete, firebrick, fix, flag, flagging, flagstone, flint, flintlike, flinty, floor, flooring, fuse, gather, glass, glue, graft, granite, granitelike, granitic, grapple, gravel, grout, gum, gunk, hard, hardhearted, heart of oak, hold, horny, include, iron, iron-hard