이어받다 = comes from 잇다 (connect, continue, succeed) + -아/어 받다 (receive) => succeed (work, tradition, etc). (잇다 + -어 becomes 이어, by an irregular conjugation of dropping ㅅ. 이어받다 is also a full word, not two words) 정신을 이어받다 = succeed/continue the spirit or ideal. 전통을 이어받다 = succeed/continue the tradition.