Motley (adjective) :  made up of many different people or things

https://www.merriam-webster.com/dictionary/motley

Colsen Whitehead, “City Limits,” from The Colossus of New York, page 2

” This place multiplies when you’re not looking. We move over here, we move over there. Over a lifetime, that adds up to a lot of neighborhoods, the motley construction material of your jerry-built metropolis”

From reading this text, i knew that the word would be describing the type of construction but I would’ve never thought about being made up of a lot things. The word helps a lot better because originally I would’ve thought it would be old material not something that involves a lot, which makes understanding the text better in the sense of an overlapping New York

Injurious (adjective): inflicting or tending to inflict injury

I came across this word while reading Plato’s Republic. The context goes:

“…and that you really agree with Thrasymachus in thinking that justice is another’s good, and the interest of the stronger, and that injustice is a man’s own profit and interest, though injurious to the weaker.” (Page 57)

Adeimantus, who was the speaker at this point in the discussion, was arguing the point that those who are (morally) just are strong and therefore should continue to be just. He also said that the weak should pursue injustice as it is the only way for them to gain power. It was already established earlier in the book that injustice can and will be punished.

The word “injurious” looks and sounds a lot like “injury”. I guessed that the definition was something along the lines of harmfulness or detrimental to ones situation or well-being because of this. Another hint was the previously mentioned idea that injustice isn’t generally beneficial to the one who commits an act of injustice. I now completely understand the word and in what context I can use it.