| stalwart(adjective, calm, strong, solid, steady) |
| stated(adjective, firm, determined, usual, regular) |
| stationary(adjective, calm, strong, solid, fixed) |
| staunch(adjective, calm, strong, secure, firm) |
| staying put(expression, adjective, calm, strong, substantial) |
| steeled(adjective, set, firm, solid, hardened) |
| stiff-necked(adjective, mean, hard, tough, determined) |
| stipulated(adjective, firm, determined, usual, regular) |
| stout(adjective, calm, strong, solid, steady) |
| strong(adjective, calm, set, firm, solid) |
| sturdy(adjective, calm, strong, firm, solid) |
| substantial(adjective, calm, strong, secure, firm) |
| sure(adjective, calm, strong, secure, firm) |
| tenacious(adjective, determined, resolute, obstinate, uncompromising) |
| thick-skinned(adjective, mean, hard, tough, harsh) |
| together(adjective, calm, strong, steady, substantial) |
| tough nut to crack(expression, adjective, idiom, mean, hard) |
| unalterable(adjective, calm, strong, fixed, constant) |
| unchangeable(adjective, calm, strong, secure, firm) |
| unchanging(adjective, set, severe, firm, solid) |