'antisplenetic' originates from the Greek-derived prefix 'anti-' meaning 'against' combined with 'splenetic', which comes from Greek 'splḗn' meaning 'spleen' and the adjective-forming element '-etikos'.

'antisplenetic' was formed in English by attaching the prefix 'anti-' to the adjective 'splenetic' (from Late Latin/Greek 'splēnētikos'), following medical usage in which humoral theory described the spleen as linked to melancholy; the modern English formation reflects this combining of elements.

Initially used in humoral and older medical contexts to indicate something acting 'against the spleen' (physically or temperamentally); it has retained that basic sense but is now rare and mainly historical or literary in use, generally meaning 'counteracting melancholy or irritability'.