appointment vs line of work

appointment and line of work both are nouns.

Word	Noun	Adjective	Verb	Adverb
appointment	Yes	No	No	No
line of work	Yes	No	No	No

As nouns, line of work is a hypernym of appointment; that is, line of work is a word with a broader meaning than appointment:

Other hypernyms of appointment include business, job, line, occupation.

appointment (noun)	line of work (noun)
the act of putting a person into a non-elective position	the principal activity in your life that you do to earn money
the job to which you are (or hope to be) appointed
(law) the act of disposing of property by virtue of the power of appointment
(usually in the plural) furnishings and equipment (especially for a ship or hotel)
a meeting arranged in advance
a person who is appointed to a job or position