Direct Opposites:
* Failure: This is the most straightforward opposite, meaning a lack of achieving desired results or goals.
* Defeat: Similar to failure, but often implies a more significant setback or loss.
Less Direct Opposites:
* Stagnation: A lack of progress or growth, meaning no advancement towards a goal.
* Mediocrity: Being average or ordinary, not striving for excellence.
* Disappointment: A feeling of sadness or dissatisfaction when expectations are not met.
* Loss: A negative outcome that involves the absence of something desired.
Antonyms:
* Unsuccessful: The literal opposite of "successful."
* Ineffective: Not achieving the intended result.
* Fruitless: Producing no result.
The best opposite of success depends on the specific context and the way you define success.