elbow vs poke at

elbow is a noun but poke at is not a noun.

Word	Noun	Adjective	Verb	Adverb
elbow	Yes	No	Yes	No
poke at	No	No	Yes	No

As verbs, poke at is a hypernym of elbow; that is, poke at is a word with a broader meaning than elbow:

Other hypernyms of elbow include nudge, prod.

elbow (noun)	poke at (noun)
the joint of a mammal or bird that corresponds to the human elbow
the part of a sleeve that covers the elbow joint
a sharp bend in a road or river
a length of pipe with a sharp bend in it
hinge joint between the forearm and upper arm and the corresponding joint in the forelimb of a quadruped

elbow (verb)	poke at (verb)
shove one's elbow into another person's ribs	to push against gently
push one's way with the elbows