Prefix-suffix Bicliques

I saw this toy at the store:

It has five prefixes and five suffixes such that each pair forms a valid word.

Can we do better than 5 of each? I ran a quick search on a dictionary-consensus wordlist, and the best¹ I could find was a 7x7:

I actually found a few dozen 7x7 sets. The one above seems well-suited to an actual toy, but the first one I found was the following, which would make for a beautifully stupid children’s toy:

There’s also a 7x8 set, but it has a few questionable word-pairs:

And if we’re willing to use medical terminology, then here’s a 10x10:

¶ Other Musings

¶ Can We expand on the original toy’s wordlist?

Yes and no. There are no prefixes we could add that work with all five of the original suffixes -ad,-at,-ail,-ay,-ug.

However, there are another 10 additional suffixes that work with p-, b-, m-, h-, r-:

-are, -ate, -atter, -ill, -ock, -od, -ole, -ound, -uff, -ush

¶ Can we make a toy with only 3-letter words?

The original toy has one two-letter suffix, -ail, which means some of the resulting words are four letters long. that’s a bit unsatisfying. If they replaced -ail with -od, then the toy would be more symmetric. Though “bod” and “mod” are admittedly questionable as words go…

Here’s an alternate set, which doesn’t have that problem, but does have a couple of its own odd or archaic words:

Here’s one with a couple “kid-friendly” naughty words - “pee” and “wee” which would paradoxically make for an excellent toy but also one that a toy company would be averse to selling.

And here’s an alternative with 2-letter prefixes and 1-letter suffixes:

Still not perfect. I understand what the toy designers resorted to -ail.

¶ Can we make a toy with only 2-letter words?

No.

You can get a 3x4 set with two letter words if you’re willing to accept exclamations: ah, am, an, ax, eh, em, en, ex, oh, om, on, ox

But there’s no 5x5 set.

¶ Stop trying to make a better toy. Let’s make a worse one.

That result up above with words like “materia-listic” was pretty silly. I wonder how big I could force the words to be in a toy like this…

Turning to the wikipedia corpus (all words used on wikipedia), I found a 5x5 set where the minimum word length is 17 and the average is 18.8. But this cheats by using both British and American spellings.

Here’s one that doesn’t rely on variant spellings. The minimum word length is only 16, but the average is 19.2. And wow! What a terrible list of words!