Implacable
(pronounced im-plak-uh-bul or im-playk-uh-bul) adjective
Definition
not possible to placate or appease; that cannot be turned from a purpose; inflexible; unalterable.
Main Example
First, it was his crusade against duplicity among analysts in major brokerage houses. Now, he is busy uncovering insider trading and other unethical practices in mutual fund companies. Over the past couple of years, New York Attorney General Eliot Spitzer has clearly established himself as an implacable foe of the double-dealing and corruption that seem to be rampant in the world of Wall Street.
Workplace Examples
Our longtime supplier's new management isn't interested in accommodating our special needs. We've pleaded with them to allow the old arrangements to continue for a while. We've even offered to pay higher prices, but they are not budging. They're implacable.
Honestly, I don't favor increasing your travel budget, but I'm not implacably opposed to the idea either. If you can provide some good, sound reasons for your request, bring them to my office and I'll consider them.
Other Examples
your commenting: "Looks like I'll have to start travelling pretty extensively. My new boss has been implacably insisting that I spend at least ten days each month visiting out-of-town customers."
Ralph Nader, a vocal and implacable critic of corporate America
advances in the fight against cancer fueling optimism that it is no longer an implacable disease; recent successes at some schools and colleges in reducing student smoking, drinking, and sex demonstrating that these vices are not implacable seductors
al Qaeda's continuing attacks on U.S. assets since the early 1990s illustrating the implacability of that organization's anti-American campaign