HSK 4
相互
xiānghù副
each other; mutual
朋友应该相互关心。
Péng you yīng gāi xiāng hù guān xīn.
Friends should care about one another.
Say it
Hold the button, say it, then let go.
Other HSK words sharing a character
Also free:
New in the HSK 3.0 word list at level 4.