This term includes men who are gay, bi, pan, m-spec, ace-spec, aro-spec, non-binary, and queer.

The term derives from Achilles, the greatest warrior among the Greeks at Troy and slayer of Hector from Homer's Iliad.

[1] The term Achillean was not traditionally used in reference to sexuality but rather to denote heroic qualities associated with Achilles, with its earliest recorded usage dating back to 1579 in the writings of William Fulke.

[3] As a descriptor, Achillean often referred to being nearly invincible with a critical weakness (an Achilles' heel), which ultimately leads to one's downfall, or to being guided by emotional motives, such as rage, rather than reason.

[4][5] In medical literature, the term Achillean related to the Achilles tendon.