plan vs be after

plan is a noun but be after is not a noun.

Word	Noun	Adjective	Verb	Adverb
plan	Yes	No	Yes	No
be after	No	No	Yes	No

As verbs, plan and be after are synonyms defined as:

plan (noun)	be after (noun)
scale drawing of a structure
a series of steps to be carried out or goals to be accomplished
an arrangement scheme

plan (verb)	be after (verb)
make plans for something	have the will and intention to carry out some action
have the will and intention to carry out some action
make or work out a plan for; devise