Okay, I THINK I figured out how the filter thingy here works.
1. Click the Settings icon on the top right of a column
2. Scroll down to 'Advanced'
3. Put a text like this in the 'Filter out by regular expressions' box:
@.*bot\s|@someone\s|some word|more words
^ This would mute ALL toots that CONTAIN
1. usernames that end in 'bot' (but not ones that have 'bot' in the middle)
2. user @someone
3. words 'some word'
4. words 'more words'
Sadly it can't seem to filter out emoji like 
Note that this ONLY mutes toots that CONTAIN these phrases, it does NOT mute USERS 😅
Thanks to @Baxter for pointing out that using '\b' instead of '\s' also makes it work at the end of toots!
@Tobi Is it using RegEx for filtering? If so, \b means word boundry, so word\b should also get you word but not words.
@Baxter Hey, that works, thanks!
@Tobi Of course! Now I'm wondering if it accounts for the whole RegEx toolset. If so, that's super powerful.
In case anyone is curious:
'.*' means "any character 0 or more times"
'\s' means "any whitespace character", so that names like "@hungrybotanist" or "@someoneelse" won't be filtered
If you only wanted to filter out "word" but not "words", you could also put a '\s' after that.
Sadly, that WON'T work if it's at the END of a toot, since the ending apparently doesn't count as whitespace. 🤔
There might be a workaround for that, I'll have to look into that.