write down vs write off

write down and write off both are verbs.

Word	Noun	Adjective	Verb	Adverb
write down	No	No	Yes	No
write off	No	No	Yes	No

As verbs, write down and write off are synonyms defined as:

Other synonyms of write down include expense.

write down (verb)	write off (verb)
reduce the estimated value of something	reduce the estimated value of something
put down in writing; of texts, musical compositions, etc.	concede the loss or worthlessness of something or somebody
	write something fluently, and without hesitation
	cancel (a debt)