Calling a woman a 'mesubuta' online is unacceptable.
Male pig; the counterpart to メス豚 in the literal sense, but not used as a slur.
Common mixed kanji-katakana spelling; especially used for the derogatory sense.
Standard kanji spelling for 'female pig'; less common for the derogatory sense.
Search-only kanji form; 牝 is an uncommon character for 'female'.
Compound of メス (female) and 豚 (pig). The derogatory sense is a metaphorical extension comparing a woman to a sow.