severe, heavy, crushing / fatal, ruinous

lesson, teaching

to teach

failure, miscarriage / mistake, fault, error

fail / make a mistake

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

failed creation; failure

loser, (a social) failure, also-ran