고유어(go-yu-eo, goyueo)
Native Korean words originally belonging to Korean without foreign or Sino-Korean influence.
When to use
Native Korean words, Exclude Sino-Korean, Exclude loanwords
The nuance
고유어 refers to words that have been used in Korean for a long time, excluding Sino-Korean words and loanwords.
순우리말(sun-u-ri-mal, sunurimal)
Pure Korean words without any mixture of Chinese characters or foreign loanwords.
When to use
Exclude Sino-Korean completely, Exclude loanwords completely, Emphasize pure words
The nuance
순우리말 strictly refers to words with no Sino-Korean or loanword influence, emphasizing pure Korean origin.
우리말(u-ri-mal, urimal)
The Korean language or words in general, including native Korean words, Sino-Korean words, and loanwords.
When to use
All Korean language, Includes native words, Includes Sino-Korean, Includes loanwords
The nuance
우리말 broadly means Korean language or words, including native, Sino-Korean, and loanwords.