thân nhau 
to be close to each other, be good friends [ thân ] : (1) intimate, close, dear; (2) person, body; (3) ninth year of the Chinese zodiac (“monkey”)
[ nhau ] : (1) together, in company, each other; (2) placenta
Most Common Compounds Set 1:
Most Common Compounds Set 2 :
thân nhau vô cùng to be very close, be very good friends hết thân nhau to stop being friends (with each other)