English is a tough language to learn. Most of us are fortunate we learned it at such an early age. It is difficult because some words have different (and sometimes opposite meaning) and others are just downright quirky.
Some words should have a clear meaning but they sure don’t. For example, the peanut is a legume, not a nut. Danish pastries were created in Austria. The cute and cuddly Koala bear is a marsupial and not a bear. Panama hats originate from Ecuador, not Panama. There is neither pine nor apple in a pineapple, no egg in eggplant and not a bit of ham in hamburger.
Now, consider these questions.
If a vegetarian eats vegetables, what does a humanitarian eat?
Why do you fill in a form by filling it out?