2. Measly. See example below (skip to :16 if you're impatient).
Why is this amusing? It could be the long "e" sound, which makes people smile by default. But let's not overthink things.
4. Mini (used as a prefix). Mini bagels, minigolf: it's all funny. Also, I might be the only person in America who still finds this hilarious:
5. Junior (used as a suffix). A friend recently told me that her children's theater company will put on a production of Shrek Jr. I have been laughing about this at random intervals ever since.
6. B.O. Do two initials count as a word? For our purposes, yes.