Answer: deep

AnswerCrossword Clue
DEEPLike the diving-board end
DEEPLike a philosopher
DEEPLike corporate "pockets"
DEEPBass
DEEPThoughtful
DEEP..-sea
DEEPHardly superficial
DEEPRequiring much thought
DEEPWord before freeze or fry
DEEPBenchley novel "The .."
DEEPFar beneath the surface
DEEPLike one end of many a pool
DEEPSea, with "the"
DEEPSerious
DEEP"... Impact" ('98 disaster film)
DEEPHard to understand, as a math problem
DEEPHeartfelt
DEEPRequiring a lot of thought
DEEPWatergate's ... Throat
DEEPWord with freeze or fry
deepin a situation beyond the range of one's capability or skill
DEEPLike a fat cat's pockets
DEEPNot shallow
DEEPWord with freeze or pit
DEEP.. Blue (Kasparov foe of '96)
DEEPAbysmal
DEEPHow still waters run
DEEPProfound
DEEPLike things that make you go "hmm ..."
DEEP"You just blew my mind, dude"
DEEPSuper philosophical, man
DEEPDifficult to understand
DEEPThought-provoking
DEEPWay down
DEEPInsightful
DEEPFull of insight
DEEPAbstruse
DEEPCavernous
DEEPDifficult to fathom
DEEPHard to fathom