effort: [15] Etymologically, effort is the ‘putting out’ or ‘showing’ of ‘force’. It comes ultimately from Vulgar Latin *exfortiāre, a compound verb formed from the prefix ex- ‘out’ and the adjective fortis ‘strong’. This passed into Old French as esforcier ‘force, exert’, from which was derived the noun esforz. English borrowed it in its later form effort. => force[effort etymology, effort origin, 英语词源]