Quick tip - you can look words up here:
http://thai2english.com/search/girl+
Personally I wouldn't use idn.bz to identify prime thai terms. the google translator it uses is very rough. It doesn't really make sense:
Girl.com in Thai
เด็กหญิง.com PRIME TERM
Punycode: xn--12cmr0a0j6b5dtc.com
http://idn.bz/rate.php?keyword=xn--1...om&language=th
Girls.com in Thai
เกิร์ล.com PRIME TERM
Punycode: xn--12c2eg2dycyd.com
http://idn.bz/rate.php?keyword=เกิร์ล.com&language=th
How can they both be prime terms for the same word?
เกิร์ล.com is a translit of "girls". Not even being close to being a prime term.