kickoff vs start-off

kickoff and start-off both are nouns.

Word	Noun	Adjective	Verb	Adverb
kickoff	Yes	No	No	No
start-off	Yes	No	No	No

As nouns, kickoff and start-off are synonyms defined as:

Other synonyms of kickoff include send-off.

kickoff (noun)	start-off (noun)
(football) a kick from the center of the field to start a football game or to resume it after a score	a start given to contestants
a start given to contestants
the time at which something is supposed to begin