Swap one word from List 1 with one word from List 2 so that the two lists have a similar - but different property. 

List 1                   List 2

RODE                 OAR

EARTH               TRIPLE

HEART               THOUGH

LUMP                 BLUR

 

Answer:

 

The two words to be swapped are HEART from List 1 and OAR from List 2:

 

In List 1, repeating the ending letter of each word at the beginning will give a new word, while in List 2, repeating the beginning letter at the end of the word will give a new word.

 

ERODE             TRIPLET

HEARTH          THOUGHT

PLUMP             BLURB

(ROAR)             (HEARTH)