we can talk about/laugh/cry at 'WTF code' or 'WTF stories', so it must be an adjective sometimes.
That doesn't follow. A noun phrase formed from two nouns doesn't automatically promote one of the nouns to an adjective. You might get annoyed at a network outage, but neither network nor outage is an adjective.
sigh This design just screams "1990s", doesn't it. It would be far better to turn the query strings into fields, and have TableSelector instances created by factory objects put together using composition.
Acronym : a word (as NATO, radar, or laser) formed from the initial letter or letters of each of the successive parts or major parts of a compound term; also : an abbreviation (as FBI) formed from initial letters : initialism