The -ment suffix is a common one in forming nouns. It’s from French, and related to the classical Latin suffix -mentum, something added to verb stems to make it “the result or product of the action”, like how enjoyment is something that’s the result of doing something you enjoy. That follows for a lot of these words—payment is a thing you pay, treatment is how you treat, equipment is things you equip. But there are words where if you drop the -ment part, you’re left with something that’s rather confusing.
Take, for example, instrument. Instru- isn’t a word. Is it from instruct? Is an instrument a thing you instruct? That does kind of make sense…
Instrument showed up in the late thirteenth century from the Old French instrument/enstrument, which had the same meaning we use for it. It’s from the classical Latin instrumentum, tool, which is from instruere, which could mean to deploy or to build/erect, but also to arrange, set in order, or inform/teach. It’s a mix of the prefix in-, meaning on, and struere, which means to construct and is from the Proto Indo European stere-, to spread. And instruere is where we get instruct, although that word came to us through the past participle instructus.
So that’s one example. There are many, many more to come.