| earsplitting(adjective, hard, severe, sharp, flat) |
| edged |
| escharotic |
| exigent |
| fermented(adjective, sharp, unpleasant, bitter, sour) |
| fierce |
| firm(adjective, strong, hard, tough, severe) |
| flat(adjective, hard, severe, sharp, rough) |
| flinty(adjective, close, strong, hard, tough) |
| foldable |
| forbidding(adjective, close, strong, hard, tough) |
| frosty(adjective, severe) |
| frowning(adjective, strong, hard, tough, severe) |
| fundamental(adjective, severe) |
| glaring(adjective, hard, severe, sharp, flat) |
| grating(adjective, hard, severe, sharp, flat) |
| green(adjective, sharp, unpleasant, bitter, sour) |
| guttural(adjective, hard, severe, sharp, flat) |
| hard-boiled(adjective, strong, hard, tough, severe) |
| hard-core(adjective, strong, hard, tough, severe) |