#!/bin/bash

((! $# )) && chop="" || { for c; do chop+="^$c$|"; done }

awk -v chop=${chop%|} '
  BEGIN{ORS=":";RS="[:\n]"}
  !length(chop) && !a[$0]++
  $0 !~ chop && !a[$0]++
'<<<"${PATH%:}"