不分高下

bùfēngāoxià
  1. equally matched
  2. not much to distinguish who is stronger

CEDICT

分不出高下。形容能力一样好，难分出输赢。

重編國語辭典

Entry Composition

1 不分 bùfēn
  1. not to distinguish; to make no distinction
  2. (LGBT slang) versatile (open to either penetrative or receptive role)
2 高下 gāoxià relative superiority (better or worse, stronger or weaker, above or below etc)

Related entries

不相上下 bùxiāngshàngxià
  1. equally matched
  2. about the same
不分轩轾 bùfēnxuānzhì
  1. well-matched
  2. equally matched