Looking at "pitambar", Vishal thinks it simply means "yellow cloth" — a describing compound like…

Why

Vishal's word-by-word reading is technically correct — 'पीत' means yellow, 'अंबर' means cloth, so the literal meaning really is 'yellow cloth', just like 'नीलकमल'. But Hindi has a third, special kind of compound where the WHOLE WORD doesn't point to its parts' literal meaning at all, but to an entirely different person or thing — this is called बहुव्रीहि समास (bahuvrihi samas). 'पीतांबर' isn't used to mean 'yellow cloth' directly; it refers to the person (traditionally Krishna or Vishnu) who wears yellow cloth — the word itself becomes an identity for someone else rather than staying its own meaning. Test it: 'नीलकमल' conjures a flower (the word IS its meaning); 'पीतांबर' conjures a person, not just cloth. His teacher is right: 'पीतांबर' points to a person — this is बहुव्रीहि समास (bahuvrihi), where the whole word signals something entirely different from its parts.