culmination vs completion

culmination and completion both are nouns.

Word	Noun	Adjective	Verb	Adverb
culmination	Yes	No	No	No
completion	Yes	No	No	No

As nouns, culmination and completion are synonyms defined as:

Other synonyms of culmination include closing, mop up, windup.

culmination (noun)	completion (noun)
a concluding action	a concluding action
the decisive moment in a novel or play	(American football) a successful forward pass in football
(astronomy) a heavenly body's highest celestial point above an observer's horizon
a final climactic stage