unneighbourly vs unneighborly

unneighbourly and unneighborly both are adjectives.

Word	Noun	Adjective	Verb	Adverb
unneighbourly	No	Yes	No	No
unneighborly	No	Yes	No	No

As adjectives, unneighbourly and unneighborly are synonyms defined as:

unneighbourly and unneighborly: not exhibiting the qualities expected in a friendly neighbor

unneighbourly (adjective)	unneighborly (adjective)
not exhibiting the qualities expected in a friendly neighbor	not exhibiting the qualities expected in a friendly neighbor