On meta there are two tags searching and search. The latter is one of the default tags - these are the tags that are automatically created on every new meta site - which essentially means that it cannot be removed.

I would suggest creating a synonym search $\to$ searching. Having two tags for the same topic could lead to confusion which tag to choose and also to inconsistent usage of tags - and, consequently, this would make searching using tags a bit difficult.

I have mentioned this a few times in chat (October 2016, April 2018). Since I have not received any feedback there, I've decided to try my luck here on meta.