buttless

As an adjective buttless

is without a butt, not having a butt.

As a noun null is

zero, nil; the cardinal number before einn.

As a noun buttress

is (architecture) a brick or stone structure built against another structure to support it.

As a verb buttress

is to support something physically with, or as if with, a prop or buttress.

As an adjective buttless is

without a butt, not having a butt.