The term 'ON 'E'' is a phrase used to describe a situation in which someone has run out of energy or enthusiasm. The crossword solutions for this term are 'EMPTY' (5 letters) and 'OUTOFGAS' (8 letters). EMPTY is a word that describes a lack of content or substance, while OUTOFGAS is a phrase that implies a lack of energy or enthusiasm. Together, these two words provide an apt description of the phrase 'ON 'E''.