The term 'Word After YES or No' can be answered with two different words, depending on the number of letters. The 6-letter word is 'Sirree, ' which is an informal way of saying 'YES' or 'CERTAINLY.' It is derived from the Scottish phrase 'sir ree, ' which means 'YES indeed.' The 5-letter word is 'Siree, ' which is another informal way of saying 'YES' or 'CERTAINLY.' It is derived from the phrase 'siree bob, ' which was popularized in the 19th century and is still used today.