Dense
Thick, Deep, Strong
い adjective
This is a single kanji with an い on the end, meaning it's probably an adjective. The kanji means dense, and this can also mean dense or thick in some contexts, like if you’re describing fog, or body hair! More generally, it can be used for anything that’s highly concentrated, so you can use it for things like deep colors, or strong coffee too!
What’s the most dense thing you can think of? A 子 (こ). Children are so full of joy, you can practically see how dense, thick and concentrated the joy is.
私は彼の髪は濃い紫色にしようかなって思ってるんだよね。
I’m thinking of dyeing his hair a deep purple.