Northwest
noun, の adjective
This word is so simple. North + West = Northwest.
ほくせい
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.
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.