General:
* Unfavorable: This is a neutral and direct term, simply indicating that something is not favorable.
* Negative: This term is slightly stronger than unfavorable, implying that something is harmful or undesirable.
* Unfortunate: This word suggests that something is regrettable or regrettable.
* Adverse: This term implies that something is harmful or damaging.
* Detrimental: This is a stronger term that implies that something is causing harm or damage.
Informal:
* Bad: This is a simple and informal term for something that is not good.
* Awful: This is a stronger term that implies something is very bad or unpleasant.
* Terrible: This is a similar term to awful, suggesting something is very bad.
Formal:
* Unfortunate: This is a more formal way of saying something is regrettable.
* Adverse: This is a more formal way of saying something is harmful or damaging.
* Detrimental: This is a more formal term that implies something is causing harm or damage.
* Prejudicial: This term suggests that something is harmful or damaging to someone's rights or interests.
Other possibilities:
* Unpleasant: This implies something is disagreeable or distasteful.
* Disadvantageous: This indicates something is not beneficial or advantageous.
* Unwanted: This suggests that something is not desired or needed.
The best word to use depends on the specific context and the desired level of formality.