RegEx word permute

demo.py

from itertools import groupby

def make_regexp(word):
    return "^{}[{}]+$".format(
        "".join(
            "(?!(.*{}){{{}}})".format(char, freq) 
            for char, freq in map(
                lambda item: (item[0], sum(1 for _ in item[1]) + 1), 
                groupby(sorted(word))
            )
        ),
        "".join(set(word))
    )

print(make_regexp("творец"))

output

sigleline
^(?!(.*а){4})(?!(.*г){2})(?!(.*ж){2})(?!(.*з){2})(?!(.*и){2})(?!(.*к){2})(?!(.*л){2})[зажигалка]+$

multiline
^(?!(.*а){4})
(?!(.*г){2})
(?!(.*ж){2})
(?!(.*з){2})
(?!(.*и){2})
(?!(.*к){2})
(?!(.*л){2})[зажигалка]+$

test.sh

w='зажигалка'; echo $w | sed 's/./&\n/g;s/.$//' | sort | uniq -c | \
sed -r 's/^\s*([0-9]+)\s*(.)$/echo \\(?!\\(.*\2\\)\\{$((\1+1))\\}\\)/e;1s/^/^/;$s/$/['$w']+$/' | \
sed ':a;N;s/\n//;ta'