hwyl, Welsh, feminine noun (plural hwyliau, verbnoun form hwylio ‘sailing, to sail’)
North Wales: /huːɨ̯l/
South Wales: /hʊi̯l/
As a loanword into English: /ˈhuːɪl/ or /hoil/ (rhyming with ‘cruel’ or ‘soil,’ with the latter pronunciation departing sufficiently from the Welsh pronunciation to sound incorrect to the Welsh ear, but recognisable nonetheless)
In its concrete and literal sense, hwyl simply means ‘sail,’ the canvas which catches the wind for a maritime vessel or a windmill. It can also mean sheet, pall, covering, or any whole white cloth of canvas or linen, but there are other words preferred for these uses. Hwyl also refers to the course one may take: a journey, path, career, route, or the idea of progress itself. In casual conversation, it means any combination of: fun, good humour, light-spiritedness, contentment within one’s own nature, having one’s wits about oneself or being witty, health and good form, and general well-being. It is often used as a word of farewell, pob hwyl, literally ‘all sail,’ conveying much the same meaning as “(wishing you) all the best” in English. The word hwyl is also used as a loanword into English, to describe the melodic chanting of preachers in Wales.
Geiriadur Prifysgol Cymru defines hwyl’s abstract and figurative connotation in this manner:
A healthy physical or mental condition, good form, one’s right senses, wits; tune (of a musical instrument); temper, mood, frame of mind; nature, disposition; degree of success achieved in the execution of a particular task; fervour (especially religious), ecstasy, unction, gusto, zest; characteristic musical intonation or sing-song cadence formerly much in vogue in the perorations of the Welsh pulpit.
Hwyl has been called the word which most comprehensively summarises the identity and condition of being Welsh: it carries within it the inspiration of awen, the sense of belonging and homeward yearning of hiraeth, and an additional passionate enthusiasm and optimism about life which is specific only to this word, never quite overlapping the meaning of any one other word.
Finnish sisu, Danish hygge, and Portuguese saudade are other words felt to carry sentiments unique to their respective cultures and nationalities, attempting to express the character, temper, and values of the people who natively speak those languages.
Immediate parent word:
Old Welsh huil ‘sail, sheet, course, journey, mood, fervour’
Cognates in sister languages:
Breton gouel or goel ‘sail’
Cornish gool or guil ‘sail’
Cognates in aunt and cousin languages:
Modern Irish Gaelic seol ‘sail, send’ is from Old Irish (and Modern Scots Gaelic) séol ‘sail, manner, course,’ itself borrowed directly from Old English (and Old Norse) seġl ‘sail.’ These may originate in a Proto-Indo-European root meaning “cut.” OW huil is unlikely to be a pure inheritance or borrowing from this source; the expected vowel conversion would give us *hail instead, which we do not find in any source.
Another potential ancestor or aunt:
Latin velum (uelum) ‘sail’ is also considered a likely related word, itself thought to originate in PIE roots meaning “weave” or “ride.” Partial inheritance from this source would easily explain the existence of OW huil instead of *hail.
If uelum is actually related etymologically to hwyl, it is probably through convergence with the similar sounds transmitted into early Celtic languages from early Germanic languages. The Q-Celtic languages (Irish and Scottish) ostensibly did not experience this convergence, and so they preserved the /s/ initial consonant from their Germanic sources, while the P-Celtic languages (Cornish, Breton, and Welsh) lost the /s/ entirely. P-Celtic languages, operating on an initial consonant mutation system, do not prefer to allow rounded vowels as the initial sound of the radical (unmutated) form of a common noun, so they add initial /g/ or /h/ to many words which would otherwise lack an initial consonant. This allows the mutation system to behave as expected, for Cornish and Breton. The /h/ in Welsh does not mutate at all, though - as a feminine noun - it does cause any following adjective such as mawr ‘big’ to take soft mutation, e.g. hwyl fawr ‘great fun.’