Question: If "reek" is used as a term to describe something that smells bad, what word of equivalent meaning would describe something that tastes bad?

Answer: 
Perhaps "**smack**" would serve. This meaning of the word is defined by [oxforddictionaries.com](https://en.oxforddictionaries.com/definition/smack) as

> 
> Have a flavour of; taste of
> 
> 
> 

and 

> 
> Suggest the presence or effects of (something wrong or unpleasant)
> 
> 
>
It's not a verb but maybe [pungent](http://www.merriam-webster.com/dictionary/pungent) [MW] would work for you

> 
> having a strong, sharp taste or smell
> 
> 
>