甚だ【はなはだ】
very, greatly, exceedingly
甚だしい【はなはだしい】
extreme, excessive, terrible, intense, severe, serious, tremendous, heavy (damage)
甚大【じんだい】
very great, enormous, serious
激甚【げきじん】
intenseness, violence, severity, vehemence, keenness
甚句【じんく】
lively song, lively dance