그렇다
geureota · TOPIK 1
to be so, to be that way
그렇다 = 그러하다 squeezed: 그러 (like that) + 하다 (to be/do)
Contraction of 그러하다. The 그 is the same 'that' as in 그것 (that thing), so the word literally says to be like that. The ㅎ left over from 하다 explains the spelling ㅀ and forms like 그래 and 그런.