As many have said, it stands for Interactive Fiction.

Since there seems to be some interest in it, the assignment I give my students is on Github here: https://github.com/agiacalone/cecs-342-lab-inform7

I have more info on IF/text adventures there as well.

Here is a reasonable starting point: https://ifcomp.org/about/if

> What’s an IF game? Very difficult to search that; Google prioritizes matches containing the English word ‘if’.

Replace "IF" with "text adventure" and you'll get better results. Their heyday was pre-Windows and the classic names to look for are Infocom (US), Scott Adams (US), and Level 9 (UK).

Edit: To add, just download Inform and try it, alongside https://ganelson.github.io/inform-website/book/WI_1_1.html which takes you step by step through stuff.

Interactive Fiction

Note well that people who enjoy Interactive Fiction (what we used to call "text adventures") ought to be the most likely people to forgive the fact that a pseudo-natural language interface is, in fact, much pickier with regard to accepted input than actual natural language. (what we used to call tolerance for "guess the verb")