银样鑞枪头yín yàng là qiāng tóu

鑞：锡铅合金，即焊锡。样子像银质其实 是焊锡做的枪头。比喻中看不中用。

例你元来苗而不秀，呸！你是个银样鑞枪头。——元·王实甫《西厢记》

英a pewter spearhead that shines like silver—an impressive-looking but useless person;