Jill is a relentless actress in pursuit of fame and fortune.
The strong wind blowing from the East was persistent and relentless, and lasted for many days.
2. A reference to a persistently hostile person, action, situation, element, etc. that is pursuing, attacking, or opposing someone or something without mercy: Sam's neighbor was a relentless hunter of wild animals.
The desert has a relentless heat and dryness for those who live there and people who travel there on a temporary visit.3. Etymology: from Latin re-, "again" + lentus, "slow."