If an older person describes a younger person as sassy, it means that she is disrespectful in a lively, confident way. It has a feminine connotation—you will not hear many boys described as sassy.
Sensible actions or decisions are good because they are based on reasons rather than emotions. Usually, you hear people use this to describe the option that they know is best even though it's not the option they really want.
This word is used to describe a lively, interesting and thought-provoking conversation or performance.
If you describe a person or his behavior as brazen, you mean that he is very bold and does not care what others think about him or his behavior. It often has a negative connotation. If someone does something that is brazen, it took a lot of guts,--not in a good way—but in a, "I can not believe he just did that!" kind of way.
respectable : (adjective)
Someone or something that is respectable is approved of by society and considered to be morally correct.
Slick, when used to describe a person, it means the person speaks and acts in a way that is likely to convince people, but is not sincere. A slick person is confident and smooth—there is a sense of suaveness associated with this word.