hoax vs pull someone's leg

hoax is a noun but pull someone's leg is not a noun.

Word	Noun	Adjective	Verb	Adverb
hoax	Yes	No	Yes	No
pull someone's leg	No	No	Yes	No

As verbs, hoax and pull someone's leg are synonyms defined as:

Other synonyms of hoax include play a joke on.

hoax (noun)	pull someone's leg (noun)
something intended to deceive; deliberate trickery intended to gain an advantage

hoax (verb)	pull someone's leg (verb)
subject to a playful hoax or joke	subject to a playful hoax or joke