noun which may take the genitive case particle 'no', noun
semi-first-class; not quite first-class; between first and second class
Describes something that is almost, but not fully, top-tier. Often used for restaurants, hotels, products, or skills that are very good but fall short of the highest rank. The 半 ('half') implies a level just below first-class.
あの店は一流半の味だが、値段は手頃だ。
That restaurant has semi-first-class taste, but the prices are reasonable.
彼の実力はまだ一流半といったところだ。
His ability is still at a semi-first-class level.
二流 is clearly second-class, whereas 一流半 sits between first and second, closer to first.
Compound of 一流 (first-class) and 半 (half), literally 'half first-class'. The exact origin is uncertain, but it follows a common pattern of adding 半 to indicate something just below a standard.