weatherboard vs weather side

weatherboard and weather side both are nouns.

Word	Noun	Adjective	Verb	Adverb
weatherboard	Yes	No	No	No
weather side	Yes	No	No	No

As nouns, weatherboard and weather side are synonyms defined as:

Other synonyms of weatherboard include windward side.

weatherboard (noun)	weather side (noun)
the side toward the wind	the side toward the wind
a long thin board with one edge thicker than the other; used as siding by lapping one board over the board below