onerous

adjective

1. burdensome, oppressive, or troublesome; causing hardship: onerous duties.
2. having or involving obligations or responsibilities, especially legal ones, that outweigh the advantages: an onerous agreement.

adjective

1. laborious or oppressive
2. law (of a contract, lease, etc) having or involving burdens or obligations that counterbalance or outweigh the advantages

adj.late 14c., from Old French onereus, honereus (14c., Modern French onéreux) and directly from Latin onerosus, from onus (genitive oneris) “burden” (see onus).