Terms for torts committed under theory of promissory estoppel?
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  <p><a href="https://legaldictionary.net/promissory-estoppel/" rel="nofollow noreferrer">The promissory estoppel doctrine allows an injured party to recover on a promise upon which he relied, and then suffered a loss as a result. ... All that must be proven is that a promise was made, and that in relying on that promise, a party suffered a loss as a result.</a></p>
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<p>What are terms for the tort or cause of action for which one might claim damages under the doctrine of promissory estoppel?</p>

<p>For example: under the theory of "negligence" a tortfeasor or his actions might be called "negligent," and one might sue for relief from "tortious negligence."</p>

<p>But under the theory of promissory estoppel, what words apply to the tort and tortfeasor?  E.g., does one sue an "unreliable" tortfeasor for "tortiously changing his mind?"</p>

<p>Promissory estoppel is part of contract law, not tort law, so someone who breaks that promise would not be a tortfeasor. You'd just say that he was in breach of the promise, as you would say that someone was in breach of contract. If you need a noun for the person, you'd probably just use "breaching party."</p>

<blockquote>
  <p>What are terms for the tort or cause of action for which one might
  claim damages under the doctrine of promissory estoppel?</p>
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<p>Courts simply use the terms <em>promissor</em>, and <em>promisee</em>. See <a href="https://www.leagle.com/decision/1994282124wn2d1581274" rel="nofollow noreferrer"><em>Havens v. C &amp; D Plastics, Inc.</em>, 124 Wn.2d 158, 171-172 (1994)</a>:</p>

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  <p>To obtain recovery in promissory estoppel, plaintiff must establish</p>
  
  <p>(1) [a] promise which (2) the promisor should reasonably expect to
  cause the promisee to change his position and (3) which does cause the
  promisee to change his position (4) justifiably relying upon the
  promise, in such a manner that (5) injustice can be avoided only by
  enforcement of the promise.</p>
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<p>Promissory estoppel sounds in equity, not tort.  The theory of recovery is simply "estoppel" - the promissor will be held to the promise, the cost of cover, and potentially to the consequential damage for breach of the promise.  The person who broke the promise is the "promissor" and the injured person is the "promissee," or more often something else entirely, unrelated to the cause.</p>

<p>Anyhow, your question appears to ask for the adjective one might apply to the promissor.  I'm not sure I have seen anything standard in this regard, and the language can be as colorful as the parties or court like.  A breach of promise is treated like a breach of contract, so any adjective one applies to a misfeasant breaching contract party one might also apply to a misfeasant breaching promissor.  I think "breaching" is probably the answer - as in, "I'm suing a breaching promissor for inequitably breaching his promise!"  Doesn't sing quite like "tortious" and "negligent" due, I'm afraid.</p>

civil-law legal-terms tort