| bulldogged |
| dauntless(adjective, strong, tough, vigorous, bold) |
| decisive(adjective, determined, serious, resolute, persistent) |
| dedicated(adjective, clear, strong, tough, severe) |
| energetic(adjective, strong, sound, tough, solid) |
| gluey(adjective, tough, thick, syrupy, tacky) |
| gritty(adjective, strong, tough, determined, steady) |
| gummy(adjective, secure, thick, tacky, sticky) |
| gutsy(adjective, strong, tough, determined, vigorous) |
| hidebound(adjective, determined, resolute, persistent, obstinate) |
| iron(adjective, strong, tough, firm, solid) |
| lasting(adjective, tough, firm, true, fixed) |
| loyal(adjective, firm, true, fixed, resolute) |
| opinionated(tough, firm, unreasonable, grim, persistent) |
| patient(adjective, strong, firm, determined, steady) |
| perseverant |
| pig-headed(adjective, determined, resolute, obstinate, stubborn) |
| recalcitrant(adjective, tough, firm, difficult, wild) |
| stable(adjective, strong, sound, secure, tough) |
| uncooperative(adjective, difficult, wild, awkward, persistent) |