retro; nostalgic; old-fashioned
Describes something that evokes a past era, often with a positive or stylish connotation. Used for fashion, design, music, and atmosphere.
Retro-style furniture is popular these days.
This café has a nice retro atmosphere, doesn't it?
She is wearing a retro-style dress.
This café has a retro feel and is relaxing.
昭和 (used adjectivally as 昭和な/昭和っぽい) describes a nostalgic feel specifically tied to the Shōwa era, whereas レトロ is a broader loanword for 'retro' or 'vintage' that isn't limited to any one period.
モダン describes a modern, contemporary style, the opposite of レトロ's old-fashioned, nostalgic style.
レトロ describes an old-fashioned style or aesthetic itself, whereas ノスタルジック describes the sentimental feeling of longing for the past.
Loanword from English 'retro', a shortening of 'retrospective' or 'retrograde'. Entered Japanese in the late 20th century.