adjective
droll
DROHL/drəʊl/
Amusing in an odd or understated way.
The host's droll offer of tea to a rubber duck amuses her guest.

Etymology
French drôle described something odd or comical and was also associated with a noun meaning “buffoon.” The English adjective carries that combination of strangeness and amusement.
In context
We couldn't afford to lose him," she declared to my aunt. "He is so awfully humorous--his droll sayings and antics keep us in a perfect roar each night at dinner.
More examples
- The novel's droll narrator notices every small absurdity.
- She gives a droll little smile as the plan falls apart.
- He describes the disastrous dinner with droll understatement.
Forms
droll · droller · drollest
drolly adverb — In an oddly amusing, understated manner.
drollery noun — Humor that is odd or understated.