drone

(noun) stingless male bee in a colony of social bees (especially honeybees) whose sole function is to mate with the queen.

(noun) an unchanging intonation. Synonyms: monotone, droning.

(noun) someone who takes more time than necessary; someone who lags behind. Synonyms: dawdler, laggard, lagger, trailer, poke.

(noun) an aircraft without a pilot that is operated by remote control. Synonyms: pilotless aircraft, radio-controlled aircraft.

(noun) a pipe of the bagpipe that is tuned to produce a single continuous tone. Synonyms: drone pipe, bourdon.

(verb) make a monotonous low dull sound. Example: "The harmonium was droning on."

(verb) talk in a monotonous voice. Synonyms: drone on.