Verb
become quiet or calm, especially after a state of agitation
lose intensity
feel less enamoured of something or somebody
Source: WordNetYou want hot days to get your fruit ripe but then you want it to cool off nicely at night so that the grapes stay on the vine longer and develop complexity. Drew Bledsoe
If you're having trouble finishing a book, it might be that you're trying to fix it as you go. Just finish the story, no matter how terrible you think that first draft is. Then let it cool off. In other words, don't look at it for a while. Then you can rewrite it. Kimberly Willis Holt
I'm comfortable only when there's a mutual attraction. That's what anyone wants. If I find out she's not attracted to me, it brings down my level of attraction to her. If I'm interested and find out she's not, I tend to cool off. Nathan Fillion
After the fight both men need to cool off. Source: Internet
It took a while after the baby was born for things to settle down again. Source: Internet
His enthusiasm cooled considerably Source: Internet