고맙다

Etymology
Cognate with 🇨🇬. From 🇰🇲

Adjective

 * 1) to be thankful; to be grateful

Etymology
attested only in conjugated forms.

The word is almost certainly a contraction of, the regularly derived adjective from the verb. In Middle Korean, had the meaning of "to be worth respecting; to be worth admiring", as would be expected from regular  adjectives. The source verb was displaced by Sino-Korean loans in the Early Modern period, when the derived adjective's semantic shift to "to be thankful" also occurred.

Adjective

 * 1) (to be) thankful
 * This adjective is often translated as a form of “to thank”.

Conjugation
is in the class of irregularly-inflected words whose stems end in. In such words with two syllables or more, vowel harmony in inflections was once followed in both standardized forms of Korean. With the 1988, the South Korean standard now ignores the vowel harmony, while it is kept in the North.

North Korean and South Korean before 1988:

South Korean since 1988: