piercing vs knifelike

piercing and knifelike both are adjectives.

Word	Noun	Adjective	Verb	Adverb
piercing	No	Yes	No	No
knifelike	No	Yes	No	No

As adjectives, piercing and knifelike are synonyms defined as:

piercing and knifelike: having or demonstrating ability to recognize or draw fine distinctions

Other synonyms of piercing include acute, discriminating, incisive, keen, penetrating, penetrative, sharp.

As adjectives, piercing and knifelike are synonyms defined as:

Other synonyms of piercing include cutting, keen, lancinate, lancinating, stabbing.

piercing (adjective)	knifelike (adjective)
having or demonstrating ability to recognize or draw fine distinctions	having a sharp or distinct edge
painful as if caused by a sharp instrument	having or demonstrating ability to recognize or draw fine distinctions
	cutting or able to cut as if with a knife
	painful as if caused by a sharp instrument