Webster's Revised Unabridged Dictionary · 1913

Onerous

Onerous , adjective

[Latin onerosus, from onus, oneris, a load, burden: compare French onéreux.]

Burdensome; oppressive.
Too onerous a solicitude. — I. Taylor
Collocations (1)
Onerous cause (Scots Law) , a good and legal consideration; -- opposed to gratuitous.