The following words share a very unusual quality that has to do with their letters, not their meanings. Can you determine what it is?

CORNY

SPOILED 

CHAINS

STAINED

PURRING

COUNTESS

SCHOOLED 

HINT:

Each word is really two words, in a manner of speaking.

 

Answer:

The alternating letters in each word spell smaller words:

CoRnY - CRY and ON

SpOiLeD - SOLD and PIE 

ChAiNs - CAN and HIS

StAiNeD - SAND and TIED

PuRrInG - PRIG and URN

CoUnTeSs - CUTS and ONES

ScHoOlEd - SHOE and COLD