cumbersome

What it means

1. Burdensome or hindering, as if a weight or drag; vexatious.

   "You can throw off your cumbersome disguise here," said Lucy, though the words could scarcely be distinguished, from her excessive agitation, Evelyn hastily caught up a cloak and cap laid ready for him, and a few minutes brought them into the sitting-room.

   1834, L[etitia] E[lizabeth] L[andon], chapter VII, in Francesca Carrara. […], volume III, London: Richard Bentley, […], (successor to Henry Colburn), →OCLC, page 54

2. Not easily managed or handled; awkward or clumsy.

   Cumbersome machines can endanger operators and slow down production.

   1 more example

   The full title of the unified system, the South Eastern & London, Chatham & Dover Railways, was decidedly cumbersome, and for the sake of convenience was shortened to the South Eastern & Chatham Railway.

   1958 November 28, “The Why and the Wherefore: South Eastern & Chatham Railway”, in Railway Magazine, page 809

3. Hard, difficult, and demanding to handle or get around with.

   A slave’s work was as cumbersome as toiling on the fields, or in the mines.

In a sentence

"You can throw off your cumbersome disguise here," said Lucy, though the words could scarcely be distinguished, from her excessive agitation, Evelyn hastily caught up a cloak and cap laid ready for him, and a few minutes brought them into the sitting-room.

1834, L[etitia] E[lizabeth] L[andon], chapter VII, in Francesca Carrara. […], volume III, London: Richard Bentley, […], (successor to Henry Colburn), →OCLC, page 54

Where it comes from

1. Middle Englishcumbyrsum
2. Englishcumbersome

From Middle English cumbyrsum, cummyrsum; equivalent to cumber (“hindrance”) + -some. Compare encumber and incumbent.