Definition of "conundrum"

“Why should I understand that, or anything else?” asked the girl. “Don’t bother my head by asking conundrums, I beg of you. Just let me discover myself in my own way.”

1815 December (indicated as 1816), [Jane Austen], chapter 2, in Emma: […], volumes (please specify |volume=I, II or III), London: […] [Charles Roworth and James Moyes] for John Murray

Besides assisting in unravelling these two etymological conundrums, the present research also made an effort to approach a greater accuracy in presenting the original sources of borrowed words.

2018, James Lambert, “Anglo-Indian slang in dictionaries on historical principles”, in World Englishes, volume 37, page 255

And while I am more concerned about the well-being of others than for myself, more hurt for them and for their losses than for my own, more worried for their futures than for the future of Martha Stewart the person, you are faced with a conundrum, a problem of monumental, to me, proportions.

2004, Martha Stewart, statement read before being sentenced to five months in prison

Herb was initially overcome by Jakarta ('The impressions of noise, chaos, tremendous crowdedness and I suppose whitelessness were perhaps the strongest, and I felt something of a stranger') and faced with the familiar conundrum ('again the sensation of the thousands of hungry people all around –happy looking often, pluckily cheerful but in fact hungry –is strange and upsetting'), but he quickly slipped into the volunteer lifestyle with relish, borrowing a bike from Soewarto, a friend from Kempen, and spending a lot of his time with volunteers, including Lance Castles and John Gare.

2011, Jemma Purdey, From Vienna to Yogyakarta