名詞 keenness:

1. a quick and penetrating intelligence
   同義詞：acuteness, acuity, sharpness
2. a positive feeling of wanting to push ahead with something
   同義詞：eagerness, avidity, avidness
3. thinness of edge or fineness of point
   同義詞：sharpness

1. The scabbard is content to be dull when it protects the keenness of the sword.
   刀鞘保護(hù)刀的鋒利，它自己則滿足于它的遲鈍。
2. The general's speech infused keenness into the men.
   將軍的演講給人們注入了激情。