The term 'WORK VERY HARD' can be summarized by two crossword solutions: SLAVE (5 letters) and TOIL (4 letters). The term 'SLAVE' is derived from the Latin word 'sclavus' which means 'SLAVE' or 'SERVANT'. It is used to describe someone who is forced to work without pay or freedom. The term 'TOIL' is derived from the Old English word 'tolian' which means 'to labor or work hard'. It is used to describe someone who works hard and long hours with little rest or reward. Both terms are used to describe someone who works very hard and with great effort.