Given the question: Question: "A sleeveless outer vestament worn by Christian clergyman is called?"  Context: "Among the paleo-orthodox and emerging church movements in Protestant and evangelical churches, in which some Presbyterians are involved, clergy are moving away from the traditional black Geneva gown to such vestments as the alb and chasuble, but also cassock and surplice (typically a full length Old English style surplice which resembles the Celtic alb, an ungirdled liturgical tunic of the old Gallican Rite), which some, particularly those identifying with the Liturgical Renewal Movement, hold to be more ancient and representative of a more ecumenical past."  Answer:
The answer is:
chasuble