| fast |
| durably(adverb, well, severely, thoroughly, strongly) |
| enduringly(adverb, well, severely, thoroughly, strongly) |
| firmly(adverb, severely, strongly, definitely, strictly) |
| fixedly(adverb, severely, thoroughly, strongly, firmly) |
| like a rock(expression, idiom, adverb, thoroughly, strongly) |
| motionlessly(adverb, well, severely, thoroughly, strongly) |
| rigidly(adverb, well, severely, thoroughly, strongly) |
| securely(adverb, severely, thoroughly, strongly, firmly) |
| solid(adverb, well, severely, thoroughly, strongly) |
| solidly(adverb, severely, thoroughly, strongly, firmly) |
| soundly(adverb, well, severely, thoroughly, strongly) |
| stably(adverb, well, severely, thoroughly, strongly) |
| stiffly(adverb, well, severely, thoroughly, strongly) |
| tightly(adverb, severely, thoroughly, strongly, firmly) |
| unflinchingly(adverb, well, severely, thoroughly, strongly) |
| immovably |
| sturdily |
| unshakably |