From Wiktionary, the free dictionary
From the first element of чел-о-век (čel-o-vek, “human”) + -як (-jak).
челя́к • (čelják) m
- ordinary person, simpleton
- “челяк”, in Речник на българския език [Dictionary of the Bulgarian Language] (in Bulgarian), Sofia: Bulgarian Academy of Sciences, 2014
- “челяк”, in Речник на българския език [Dictionary of the Bulgarian Language] (in Bulgarian), Chitanka, 2010