Burdensome

a.

1.

Grievous to be borne; causing uneasiness or fatigue; oppressive. The debt immense of endless gratitude So burdensome. - Milton.

Adj.

1.

burdensome - not easily borne; wearing; "the burdensome task of preparing the income tax return"; "my duties weren't onerous; I only had to greet the guests"; "a taxing schedule" Synonyms: onerous, taxing

Herculean, annoying, backbreaking, besetting, crushing, cumbrous, demanding, distressing, effortful, encumbering, exacting, exhausting, exigent, forced, grievous, grinding, grueling, hampering, hard-earned, hard-fought, harsh, heavy, hefty, impedimental, impeding, impeditive, incumbent, killing, labored, laborious, lumpish, massive, onerous, operose, overburdensome, painful, plaguey, punishing, strained, strenuous, superincumbent, taxing, toilsome, tough, troublesome, tyrannous, unwieldy, uphill, vexatious, wearing, wearisome, wearying, weighty, worrisome, worrying