Having a significant effect on the course of one's life.(adjective)
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Use "lifechanging" in a sentence
"I can testify, first hand, that when I did 40 days of giving last year (before my 40th birthday), it was lifechanging."
"What happened next was lifechanging for the officer, and we complain about British Courts, what on earth were the jury thinking. on March 15, 2009 at 10: 07 pm | Reply Peter de Vries"
"I have some plans for the next year, that are a bit scary and lifechanging."