Answer:

BETRUE

Answer	Crossword Clue
BETRUE	The Beach Boys' ".. to Your School"
BETRUE	Not cheat
BETRUE	Show allegiance

BETRUE	".. to Your School" (Beach Boys tune)
BETRUE	"To thine own self ... . . . "
BETRUE	"To thine own self ...": Polonius
BETRUE	"To thine own self ....."
BETRUE	Not stray
BETRUE	Stay faithful