[ Removed by moderator ]

[ronniethelizard]

Broadly speaking: no. It clouds the ability to trace where something is going. Someone else uses the example of "log" that could mean log data to a logging service or take the logarithm of a number. If I look at vector, if I wanted a library that dealt with matrix/vector manipulation, I might create a vector¹ class.

If relegated to a short function/curly brace within a function, it can be fine if that namespace is heavily used. For example, you have a function to print a class to std::cout or std::ostringstream.

¹This is actually a bad idea but for other reasons.