Meaning of “yoki (よき)”
If young Japanese use this (especially Japanese girl use this), it might be a teenage slang.
It means good or nice.
Basically “yoki(良き)” is an almost ancient word.
But these days young people feel this classic style word is cool and fresh, and they started to use it as a teenage slang.
A: Look, he is so cute, isn’t it?
B: Oh, yokiyoki!
A: And he is also tall!
B: Ohh, more yoki!