Relentless is a adjective that derives from the Latin word implacabĭlis. The concept is used to qualify that cannot be placated .

He verb placate , in turn, refers to calm, appease or temper something . Therefore, the relentless cannot be alleviated, weakened or dominated . For example: "The government said it will be relentless with businesses that sell alcoholic beverages to minors", "A judge must always be relentless with murderers", "The Egyptian striker was relentless in the first part of the match: he scored three goals in just half an hour".
It is possible to understand the notion of implacable in different ways. Usually the term is used with reference to who has no contemplations or mercy and take advantage of all his power or ability to meet a goal or reach a goal.
Imagine that a teacher orders her students write a three page text on Second World War . Students have a week to complete the task and deliver the work. When the delivery day arrives, the teacher is relentless: the one who did not write, is qualified with a 1 . The educator does not accept any justification or grant an extra term to anyone.
A relentless police , meanwhile, he is the one who fulfills his duty in a responsible manner and with professionalism and effort. When patrolling, he is always attentive and if he detects an irregular situation or a suspicious individual, he immediately approaches to know what happens. If you discover a crime or a fault, proceed to act as mandated by the law , without tolerating excuses.