noun
tip of the nose
Only when written 鼻先
Refers specifically to the physical tip of the nose.
犬が鼻先でドアを押した。
The dog pushed the door with the tip of its nose.
noun
right in front of one; under one's nose
Only when written 鼻先
Used for something happening or placed very close to one's face or immediate vicinity, often with a nuance of surprise or annoyance.
彼は鼻先でドアを閉められた。
The door was shut right in his face.
犯人は警察の鼻先で逃げた。
The culprit escaped right under the police's nose.
noun
Extended use for the tip or end of a long, narrow object, such as a peninsula or a tool. Less common than the nose-related senses.
岬の鼻先に灯台が立っている。
A lighthouse stands at the tip of the cape.