The clearest term for someone who doesn’t keep their word is usually “promise-breaker.” Depending on the reason and severity, you might also call the person unreliable, untrustworthy, undependable, flaky, or say that they renege on promises. The terms are not interchangeable: some describe inconsistency, while others imply deliberate dishonesty.
Useful Descriptors for “Someone Who Doesn’t Keep Their Word” at a Glance
- Promise-breaker
- Unreliable
- Untrustworthy
- Undependable
- Flaky
- Inconsistent
- Insincere
- Deceitful
- Noncommittal
- Someone who reneges on promises
Choose the Word for “Someone Who Doesn’t Keep Their Word” Carefully
If someone simply fails to follow through, unreliable or undependable is usually fairer than calling them deceitful. If they repeatedly make commitments they never intend to honor, untrustworthy or deceitful may be more appropriate. For everyday social plans, flaky is common but informal.
Promise-breaker
The most direct noun for someone who makes a promise and then fails to keep it.
Example: “After cancelling again, he was starting to get a reputation as a promise-breaker.”
Unreliable
A broad and neutral description for someone whose words or actions cannot consistently be depended on.
Example: “She means well, but she can be unreliable when it comes to commitments.”
Untrustworthy
Stronger than “unreliable.” It suggests that the person’s word should not be trusted.
Example: “If someone repeatedly breaks important promises, others may begin to see them as untrustworthy.”
Undependable
Similar to “unreliable,” with an emphasis on not being someone you can count on.
Example: “He is friendly, but unfortunately he is undependable when deadlines matter.”
Flaky
Informal. Often used for someone who cancels plans, changes their mind, or fails to follow through.
Example: “I like her, but she’s a bit flaky about making plans.”
Inconsistent
A softer description that focuses on changing behavior rather than accusing the person of dishonesty.
Example: “His promises are inconsistent with what he actually does.”
Insincere
Appropriate when promises seem not to have been meant genuinely in the first place.
Example: “Her apology sounded insincere because the same promise had been broken several times.”
Deceitful
Use only when there is deliberate dishonesty. Breaking a promise by itself does not automatically make someone deceitful.
Example: “If he knowingly makes promises he has no intention of keeping, ‘deceitful’ may be accurate.”
Noncommittal
Describes someone reluctant to make a firm commitment. It is related to the idea, but does not necessarily mean they have broken their word.
Example: “He stayed noncommittal rather than promising something he might not be able to deliver.”
Someone who reneges on promises
A precise phrase for a person who goes back on an agreement or commitment after making it.
Example: “They agreed to the terms and then reneged on the promise a week later.”
What Does “Renege” Mean?
To renege means to go back on a promise, agreement, or commitment. It is more precise than many personality labels because it describes the action rather than defining the whole person. For example, “The company reneged on its commitment” is often stronger and clearer than calling the company “unreliable.”
Words That Are Similar but Not the Same
Indecisive and wishy-washy describe difficulty making or sticking to a decision, but they do not necessarily mean someone has broken a promise. Commitment-phobic describes reluctance to commit, especially in relationships, rather than failing to keep one’s word. Use these only when that is the behavior you actually mean.
The Best General Choice for “Someone Who Doesn’t Keep Their Word”
If you want a phrase that is accurate without making assumptions about motive, “unreliable” is usually the safest general description. If the broken promise itself is the point, “promise-breaker” or “someone who reneges on promises” is more precise.