Synonyms and related words :
close, close-knit, close-textured, close-woven, closed, compact, compacted, compressed, concentrated, concrete, condensed, congested, consolidated, crammed, crammed full, crowded, dense, firm, gluey, hard, heavy, hermetic, holeproof, impassable, impenetrable, impervious, jam-packed, jammed, massive, nonporous, nonpuncturable, packed, punctureproof, sealed, serried, solid, substantial, thick, thick-growing, thickset, unpassable, unperforable, unpierceable, viscid, viscose, viscous