The term 'within reason' can be broken down into three crossword solutions: SANE (4 letters), DOABLE (6 letters), and SANELY (6 letters). SANE is an adjective meaning 'mentally sound, rational, and sensible'. DOABLE is an adjective meaning 'capable of being done or accomplished'. SANELY is an adverb meaning 'in a SANE manner'. Together, these three words form the phrase 'within reason', which means 'as far as is reasonable or practical'.