NPR Weekend Edition Sunday Puzzle
July 2, 2011
Will Shortz

The five-letter words below share a quality that changes them into other words in an unusual way. Can you tell what it is?

CAMEL
PARTY
FORTH
SKIMP
EARLY
BOOTH

Answer:

The last letter of each word can be dropped to leave a valid word. The last letter of that word can then also be dropped to leave a second valid word:

CAMEL - CAME - CAM
PARTY - PART - PAR
FORTH - FORT - FOR
SKIMP - SKIM - SKI
EARLY - EARL - EAR
BOOTH - BOOT - BOO