window dressing

(noun) a showy misrepresentation intended to conceal something unpleasant. Synonyms: facade, window dressing.

(noun) the decoration of shop windows. Synonyms: window dressing.

(verb) make something appear superficially attractive. Synonyms: dress up, window-dress. Examples: "The researcher tried to dress up the uninteresting data." "Don't try to dress up the unpleasant truth."