A thumbs-down gesture indicating disapproval.
The gesture itself is the worldly recognized symbol of disapproval, disliking, or not agreeing.
And the meanings the emoji is used in are absolutely the same. For example, it may serve as a sign of the fact that someone didn't like what they saw or heard at all. It may be used instead of saying "no" to an unpleasant offering, and so on.
Thumbs Down was approved as part of Unicode 6.0 in 2010 under the name “Thumbs Down Sign” and added to Emoji 1.0 in 2015.
U+1F44E
? Thumbs down sign