Sharpened is a verb. It describes the action of making something sharp.
sharpened
The part of speech for this particular word is a noun.
part of speech
The part of speech for "answer" is a noun.
what part of speech is beneath
adverb
Your canine teeth can be sharpened by going to your dentist, where he/she will probably add a contour in place, but if you mean 'sharpened' like a pencil sharpened, then talk to your dentist about that.
to sharpen, sharpened, sharpened. sharp = an adjective.
The part of speech for "explicit" is an adjective.
The part of speech for "lecturer" is a noun.
The part of speech for "rapid" is an adjective.
The part of speech for "breezy" is an adjective.