- bitter
- eager
- fierce
- keen
- severe
- sharp
- stinging
- violent
Synonyms for acer
- acerbus – bitter, dark, gloomy, rigorous, shrill
- acidus – sharp, sour
- asper – fierce, harsh, rough, severe, violent
- contentus – content, contented, eager, satisfied, strained, stretched, zealous
- districtus – busy, hesitating, severe, strict
- efferus – fierce, savage, undomesticated, untamed, wild
- expetens – desirous, eager
- ferus – fierce, savage, untamed, wild
- gravis – burdensome, grievous, heavy, important, serious, severe, unwholesome, weighty
- intrepidus – eager, hot, undaunted, unshaken
- silex – flint, hard stone, rock, sharp
- silicis – flint, hard stone, rock, sharp
- vehemens – furious, impetuous, vehement, violent