mountain rivers

山側: mountain side / 山川: mountain rivers

mountainside

to be mistaken for; to be confused with

serious face; straight face; sober face

he / distal demonstrative, something far off removed from both speaker and listener: that / boyfriend

distal demonstrative, something far off removed from both speaker and listener: that, yon / particularly, male personal third person pronoun: he / by extension from he: boyfriend

he; boyfriend

(archaic) a woman's brother (regardless of age difference) / (archaic) a woman's lover or husband / (archaic) a familiar man

elder/older brother / honorific referencing an older brother figure