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reason for living; something one lives for; purpose in life; raison d'être; ikigai
孫の成長を見届けることが祖父の生きがいだ。
Watching his grandchild grow up is what gives my grandfather purpose.
退職後にボランティア活動が新たな生きがいになった。
After retirement, volunteer work became a new reason for living.
自分の生きがいを見つけることが幸せへの第一歩だ。
Finding your purpose in life is the first step toward happiness.