self-defeating
Definitions
Acting to prevent one's own success or goals.
Containing the seeds of its own failure or destruction.
Ineffective because the methods used undermine the intended outcome.
Examples
His constant criticism of his teammates proved to be self-defeating, as it only served to lower morale and reduce their overall performance.
Trying to force a creative breakthrough when you are exhausted is often a self-defeating strategy.
Synonyms
counterproductive self-destructive futile self-sabotaging unhelpful