From cumber + -ous.
cumbrous (comparative more cumbrous, superlative most cumbrous)
- Unwieldy because of its weight; cumbersome.
- He sunk beneath the cumbrous weight. — Swift.
- That cumbrous and unwieldy style which disfigures English composition so extensively. — De Quincey.
1946, Bertrand Russell, chapter 1, in History of Western Philosophy:
- In the course of thousands of years, this cumbrous system developed into alphabetic writing.
- (obsolete) Giving trouble; vexatious.
- A cloud of cumbrous gnats. — Spenser.