Unwelcome means not wanted or not gladly received. When something is unwelcome, people wish it hadn't arrived or happened. An unwelcome guest is someone who shows up when they weren't invited or when their presence makes others uncomfortable. An unwelcome surprise might be finding out you have extra homework over the weekend, or discovering that your favorite book has been chewed up by the dog.

It carries a strong feeling of being actively not wanted. Unwelcome news about a canceled field trip disappoints everyone. Unwelcome advice is when someone tells you what to do when you didn't ask for their opinion.

Notice that unwelcome describes how the receiver feels, not the giver's intentions. A friend might offer help with the best intentions, but if you want to solve the problem yourself, that help can feel unwelcome. The opposite of unwelcome is welcome: eagerly anticipated, gladly received, or warmly embraced.