| fanatic |
| fanatical |
| flinty(adjective, strong, hard, tough, severe) |
| foolhardy(determined, impulsive, stubborn, reckless, impetuous) |
| forbidding(adjective, strong, hard, tough, severe) |
| frowning(adjective, strong, hard, tough, severe) |
| goatish |
| goatlike |
| hang-tough(adjective, strong, hard, tough, severe) |
| hang tough(expression, tough, sharp, difficult, awkward) |
| hanging(adjective, determined, resolute, obstinate, uncompromising) |
| hanging tough(expression, adjective, mean, hard, determined) |
| hard-boiled(adjective, mean, strong, hard, tough) |
| hard-core(adjective, strong, hard, tough, severe) |
| hard-headed |
| hard-hearted(adjective, mean, hard, harsh, inflexible) |
| hard-line(adjective, strong, hard, tough, severe) |
| hard-shell(adjective, strong, hard, tough, severe) |
| harsh(adjective, mean, strong, hard, tough) |
| heady(determined, fixed, stubborn, willful, dogmatic) |