Have you heard of etymology?
Etymology means the study of the origin of a word. Why is this important? This is so we can understand why English is difficult.
You see, many English words were stolen and/or borrowed from many different languages (Germanic, Latin, French, etc.) and evolved into something more unique in the present.
For example the word: DEBILITATING.
This word is initially taken from the Latin word DEBILITAS.
The word DEBILITATING means: “weaken, impair the strength of, enfeeble, make inactive or languid,” [etymonline.com]
Now you may be asking, how did the word debilitas transform?
To break down the word: The prefix De- is also used as a prefix in Latin, usually meaning “down, off, away, from among, down from,” but also “down to the bottom, totally” hence “completely” (intensive or completive), which is its sense in many English words.
As a Latin prefix it also had the function of undoing or reversing a verb’s action, and hence it came to be used as a pure privative — “not, do the opposite of, undo” — which is its primary function as a living prefix in English, as in defrost (1895), defuse (1943), de-escalate (1964), etc. In some cases, a reduced form of -dis.
The second syllable – BIL- was associated with a Russian revolutionary socialist named Bolshevik. He was seen as a great leader and his name literally means greater. It is also from a PIE root *bel, which means strong. Due to Bolshevik’s revolutionary changes within Russia in 1917, the word debilitas has become part of the English language.
So when we think of the word debilitating, it’s a helpful reminder that what was once a mere non-existing word now means to weaken or impair the strength of someone/something.
I hope this is helpful!