This article is from the Puzzles FAQ, by Chris Cole firstname.lastname@example.org and Matthew Daly email@example.com with numerous contributions by others.
What is the longest word all of whose contiguous subsequences are words?
This problem was discussed in _Word Ways_ in 1974-5. In August 1974,
Ralph Beaman, in an article titled "Word Torture", offered the word
SHADES, from which one obtains HADES, SHADE; ADES, HADE, SHAD; DES, ADE,
HAD, SHA; ES, DE, AD, HA, SH; S, E, D, A, H. All of these are words
given in Webster's Third.
Since that time, a serious search has been launched for a seven-letter
word. The near misses so far are:
Date Person Word Missing Aug 74 Ralph Beaman GAMINES INES, GAMI, NES, INE Nov 74 Dmitri Borgmann ABASHED INE, NES, ABASHE, BASHE, ASHE (all in OED) May 75 David Robinson GUNITES GU, GUNIT (using Webster's Second) May 75 David Robinson ETAMINE ETAMI, TAMI (using Webster's Second) May 75 Ralph Beaman MORALES RAL (using Webster's Second) Aug 75 Tom Pulliam SHEAVES EAV (using Webster's Second)