一头儿沉
yī​tóu​r​chén

to be partial

  1. 一 yī numeral
    one
    one; the number 1; single; alone
  2. 头 頭 tóu nounlocative
    top
    the top, end, or tip of an object; the beginning or end of an event
  3. 儿 兒 r particleaffix
    [erhua suffix]
    A suffix attached to a word to form a retroflex ending, often indicating a small size, a sense of familiarity, or turning a word into a noun.
  4. 沉 chén adjective
    heavy
    Having great weight or feeling heavy and uncomfortable