a boring or unenterprising person

you're just a deadhead

a fan of the rock group the Grateful Dead

a faded flower head

a passenger or member of an audience with a free ticket

a sunken or partially submerged log

most boating accidents begin small, as a disabled engine or a collision with a deadhead

remove dead flower heads from (a plant)

deadhead and spray rose bushes

(of a commercial driver) complete a trip in a train or other vehicle with no passengers or cargo

they deadhead back to Denver on eastbound trains