unfavorable vs unfavourable

unfavorable and unfavourable both are adjectives.

Word	Noun	Adjective	Verb	Adverb
unfavorable	No	Yes	No	No
unfavourable	No	Yes	No	No

As adjectives, unfavorable and unfavourable are synonyms defined as:

unfavorable and unfavourable: (of winds or weather) tending to hinder or oppose

As adjectives, unfavorable and unfavourable are synonyms defined as:

As adjectives, unfavorable and unfavourable are synonyms defined as:

unfavorable and unfavourable: involving or creating circumstances detrimental to success or effectiveness

Other synonyms of unfavorable include disadvantageous.

unfavorable (adjective)	unfavourable (adjective)
(of winds or weather) tending to hinder or oppose	(of winds or weather) tending to hinder or oppose
not encouraging or approving or pleasing	not encouraging or approving or pleasing
involving or creating circumstances detrimental to success or effectiveness	involving or creating circumstances detrimental to success or effectiveness