| biconcave | (adjective) concave on both sides | Synonyms: concavo-concave |
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| brave | (adjective) possessing or displaying courage; able to face and deal with danger or fear without flinching | Synonyms: courageous |
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| (adjective) invulnerable to fear or intimidation | Synonyms: audacious, dauntless, fearless, hardy, intrepid, unfearing |
| (adjective) brightly colored and showy | Synonyms: braw, gay |
| concave | (adjective) curving inward | - |
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| grave | (adjective) causing fear or anxiety by threatening great harm | Synonyms: dangerous, grievous, life-threatening, serious, severe |
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| (adjective) of great gravity or crucial import; requiring serious thought | Synonyms: grievous, heavy, weighty |
| (adjective) dignified and somber in manner or character and committed to keeping promises | Synonyms: sedate, sober, solemn |
| planoconcave | (adjective) flat on one side and concave on the other | - |
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| suave | (adjective) smoothly agreeable and courteous with a degree of sophistication | Synonyms: bland, politic, smooth |
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| (adjective) having a sophisticated charm | Synonyms: debonair, debonaire, debonnaire |