headless

adjectives

not having a head or formed without a head
"the headless horseman"; "brads are headless nails"
headless
antonym
headed
is similar to
lacking a head or a clearly defined head
"acephalous worms"
acephalous
is similar to
having had the head cut off
"the beheaded prisoners"
beheaded, decapitated
not using intelligence
brainless, headless