Answer:
Solar energy (energy from the sun) for example, is considered a renewable energy resource, but it is not technically truly renewable, as the sun will eventually run out. So some renewable energy resources aren't actually "renewable" in the strictest sense of the word.
However, the sun is expected to last another several billion years, and it's pouring out the energy whether we bother to use it or not, so whether it's technically renewable or not is a minor quibble.