Verb (5-dan, る, transitive)
1. to give up (all thoughts of); to abandon; to despair of
だからそんな風にさっぱりと思い切れなかったのよ。That's why I couldn't just put it behind me so cleanly.
Verb (5-dan, る, intransitive)
2. to make up one's mind; to make a decision; to decide
ずっと気になってたことを思い切って聞いてみる。I finally worked up the courage to ask about something I had been wondering about for a long time.