date vs D-day

date and D-day both are nouns.

Word	Noun	Adjective	Verb	Adverb
date	Yes	No	Yes	No
D-day	Yes	No	No	No

date (noun)	D-day (noun)
sweet edible fruit of the date palm with a single long woody seed	date of the Allied landing in France, World War II
a meeting arranged in advance
a participant in a date
the specified day of the month
the present
the particular day, month, or year (usually according to the Gregorian calendar) that an event occurred
a particular day specified as the time something happens

date (verb)	D-day (verb)
assign a date to; determine the (probable) date of
provide with a dateline; mark with a date
stamp with a date
go on a date with
date regularly; have a steady relationship with