Tautology is a complicated term that means saying the same thing twice. It's considered bad use of language.
Unfortunately, however, there are numbers of word pairs that are tautologies that have crept into common use. Here are some examples:
Swap out - this seems to be more commonly used in US English. Swap means to change something. I often read the term "swap out" as in, he said he would swap out the batteries so the torch would work. Swap would have done fine alone.
Sort out - we can sort somet
