It implies that something is not entirely trustworthy or reliable, and there are good reasons to be hesitant or skeptical.
Here are some ways to use the word:
* "The evidence presented was dubious at best, leaving many questions unanswered."
* "Her claims of innocence were met with dubious looks from the jury."
* "The politician's promises seemed dubious, given his history of broken promises."
Synonyms for dubious:
* Suspicious
* Questionable
* Uncertain
* Unreliable
* Unclear
* Unsure
* Doubtful
* Skeptical
* Unconvincing
Antonyms for dubious:
* Certain
* Trustworthy
* Reliable
* Clear
* Convincing
* Undisputed
* Unquestionable