lot vs vacant lot

lot and vacant lot both are nouns.

Word	Noun	Adjective	Verb	Adverb
lot	Yes	No	Yes	No
vacant lot	Yes	No	No	No

As nouns, vacant lot is a hyponym of lot; that is, vacant lot is a word with a more specific, narrower meaning than lot:

Other hyponyms of lot include car park, park, parking area, parking lot, building site.

lot (noun)	vacant lot (noun)
anything (straws or pebbles etc.) taken or chosen at random	a lot on which there are no permanent buildings
an unofficial association of people or groups
any collection in its entirety
a parcel of land having fixed boundaries
(often followed by `of') a large number or amount or extent
your overall circumstances or condition in life (including everything that happens to you)

lot (verb)	vacant lot (verb)
administer or bestow, as in small portions
divide into lots, as of land, for example