見みかけ倒だおし

noun which may take the genitive case particle 'no', noun

all show and no substance; not as good as it looks

Describes something that appears impressive or strong at first glance but turns out to be weak, worthless, or disappointing upon closer inspection. Often used for people, products, or claims.

• あの選せん手しゅは見みかけ倒だおしで、試し合あいでは全まったく活かつ躍やくしなかった。

  That player was all show and no substance; he didn't perform at all in the match.