Third-person singular simple present indicative form of lighten.(verb)
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Use "lightens" in a sentence
"As it quiets, the skin lightens and the reflectivity is less noticeable."
"Everybody was looking at me ... then all of a sudden everybody starts to smile and talk, the mood just kind of lightens up."
""He can say whatever about me ... but there are so many women like me, in my situation, that I just feel when there is this laughter, if you are in that situation out there, it kind of lightens it.""