opposite; contrary
相 · 9 strokes
Depicts an eye (目) looking at a tree (木). Based on the original meaning "look at". The meaning of this character has shifted over time to "compare" and "each other".
反 · 4 strokes
Pictograph of a hand (又) climbing a cliff (厂). Based on original meaning "climb", now written as 扳. The meaning later shifted to "pull" and "reverse".