| Main Entry: | |
| Part of Speech: | adjective |
| Definition: | hard, tough; inflexible |
| Synonyms: | adamant, adamantine, cruel, dense, ferric, ferrous, firm, heavy, immovable, implacable, indomitable, inexorable, insensible, obdurate, relentless, rigid, robust, steel, steely, strong, stubborn, thick, unbending, unyielding |
| Notes: | ferrum is the Latin name for iron, from which its chemical symbol Fe is derived; iron exists in various states of impurity and it is processed to produce cast iron, wrought iron, etc. and steel (steel is iron to which carbon and other things have been added) |
| Antonyms: | flexible, soft, weak |
| Main Entry: | hard |
| Part of Speech: | adjective |
| Definition: | rocklike |
| Synonyms: | adamantine, callous, compact, compacted, compressed, concentrated, consolidated, dense, firm, hardened, impenetrable, indurate, indurated, inflexible, iron, packed, rigid, rocky, set, solid, stiff, stony, strong, thick, tough, unyielding |
| Antonyms: | flexible, malleable, pliable, pliant, soft, yielding |
| Main Entry: | inflexible |
| Part of Speech: | adjective |
| Definition: | stubborn |
| Synonyms: | adamant, adamantine, determined, dogged, dyed-in-the-wool, firm, fixed, hard, hard-and-fast, immovable, immutable, implacable, indomitable, inexorable, intractable, iron, obdurate, obstinate, relentless, resolute, rigid, rigorous, set, set in one's ways, single-minded, stand one's ground, staunch, steadfast, steely, stiff, strict, stringent, unadaptable, unbending, unchangeable, uncompliant, uncompromising, unrelenting, unswayable, unyielding |
| Antonyms: | flexible, reasonable, willing, yielding |
| Main Entry: | obdurate |
| Part of Speech: | adjective |
| Definition: | pigheaded, stubborn |
| Synonyms: | adamant, bullhead, callous, cold fish, dogged, firm, fixed, hanging tough, hard, hard-boiled, hard-hearted, hard-nosed, harsh, heartless, immovable, implacable, indurate, inexorable, inflexible, iron, mean, mulish, obstinate, perverse, relentless, rigid, set in stone, stiff-necked, thick-skinned, tough, tough nut to crack, unbending, uncompassionate, uncompromising, uncooperative, unemotional, unfeeling, unimpressible, unrelenting, unshakable, unsympathetic, unyielding |
| Antonyms: | amenable, gentle, submissive, susceptible, yielding |
| Main Entry: | secure |
| Part of Speech: | adjective |
| Definition: | fastened, stable |
| Synonyms: | adjusted, anchored, bound, buttoned down, fast, firm, fixed, fortified, immovable, iron, locked, nailed, safe and sound, set, solid, solid as a rock, sound, staunch, steady, strong, sure, tenacious, tight |
| Antonyms: | loose, moving, unfastened, unfixed, unsecure, unstable |
| Main Entry: | tenacious |
| Part of Speech: | adjective |
| Definition: | strong, unyielding |
| Synonyms: | adamant, bound, clinging, coherent, cohesive, determined, dogged, fast, firm, forceful, inflexible, intransigent, iron, meaning business, mulish, obdurate, obstinate, persevering, persistent, persisting, pertinacious, possessive, purposeful, relentless, resolute, retentive, set, solid, spunky, stalwart, staunch, steadfast, stout, strong-willed, stubborn, sturdy, sure, tight, tough, true, unforgetful, unshakable, unswerving |
| Antonyms: | surrendering, weak, yielding |
| Main Entry: | gray |
| Part of Speech: | adjective |
| Definition: | silver |
| Synonyms: | ash, ashen, cinereal, clouded, dappled, dingy, dove, drab, dusky, dusty, grey, heather, iron, lead, leaden, livid, mousy, neutral, oyster, pearly, peppery, powder, sere, shaded, silvered, silvery, slate, smoky, somber, stone |
| Notes: | the distinction in spelling between British grey and American gray is recent, popping up in Samuel Johnson's dictionary |
| Main Entry: | metallic |
| Part of Speech: | adjective |
| Definition: | made of metal |
| Synonyms: | fusible, geologic, golden, hard, iron, leaden, metallurgic, mineral, ory, rocklike, silvery, stannic, tinny |
| Main Entry: | hard-bitten |
| Part of Speech: | adjective |
| Definition: | hard |
| Synonyms: | adamantine, callous, compact, compacted, compressed, concentrated, consolidated, dense, firm, hard as nails, hard-handed, hardened, hardy, impenetrable, indurate, indurated, inflexible, iron, packed, rigid, rocky, rugged, set, solid, stiff, stony, strong |