Noun and の adjective
ほくせい
ひこうきは、北西にむかっています。
The airplane is heading northwest.
ポートランドから車で一じかん半ほど北西の方にいくと、シーサイドというまちにつきます。
If you drive about an hour and a half northwest from Portland, you will arrive at a city called Seaside.
ここから北西の方角のどこかに、パンストを落とした。
I lost my pantyhose somewhere northwest of here.
This word is so simple. North + West = Northwest.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.