burdensome

Concise Oxford English Dictionary © 2008 Oxford University Press:
burden/ˈbɜːdn/

▶noun

• 1 a heavy load.

• 2 a cause of hardship, worry, or grief.

  ■ the main responsibility for a task.

• 3 a ship's carrying capacity.

• 4 the main theme of a speech, book, or argument.

• 5 archaic the refrain or chorus of a song.

▶verb

• 1 load heavily.

• 2 cause worry, hardship, or grief to.

– phrases
burden of proof the obligation to prove an assertion.

– derivatives
burdensome adjective.

– origin OE byrthen, of W. Gmc origin; rel. to bear1.