Something gussied up has been made more attractive, but in a showy or gimmicky way, so it’s often not intended to be a compliment. It can also refer to dressing in one’s finery for some special occasion, when it is intended to be taken more straightforwardly. It is usually considered to be an American expression, dating from the late 1930s or thereabouts.

to tell someone to calm down and relax.

adverb. A phrase implying that you are dressed sharp, or stylishly; like a homosexual might dress - but still staying true to your gender. (not to be confused with cross dressing - which is to dress as the opposite gender)

Usually only applied to males.