知之甚微

zhīzhīshènwēi
to know very little about

CEDICT

Entry Composition

1 知 zhī
  1. to know
  2. to be aware
2 之 zhī
  1. (possessive particle, literary equivalent of 的 de)
  2. him
  3. her
  4. it
3 甚微 shènwēi
  1. very small
  2. very little
  3. scant
  4. minimal