Douce is an adjective one hears in the north of this island. "She keeps a douce house", said a friend to me recently; she was complimenting a Donegal neighbour for keeping her house tidy and comfortable. Douce can also mean gentle, kindly and sweet-tempered in Co Down; and in Antrim, so the invaluable Ballymena Observer tells me, the adjective is applied to elderly housewives. Because of their tidiness or of their kindliness, I wonder? - our author, W.J. Knowles, didn't elaborate. The word is found in Scotland and in northern England. It's from Middle English douce, dowce, from Old French dous, later doux (feminine douce), from Latin dulcis, sweet. Mary Boyle, a native of the Rosses, asked about the word.
A recent visitor from Co Down to my humble sheiling in Wicklow remarked that my aizins needed attention. Aizins, or easings, if you wish, are eaves. I found the word in Hume's Dialect of Down (1890); Simmons's glossary of south Donegal words, written in the same year, has it as well, as has the above-mentioned Ballymena Observer from Antrim. As the word is found in Scots and in the north of England, it is no surprise that it travelled to Ulster. Its origin is the older eavesing, representing Old English efesung, a verbal noun. Langland's Piers Plowman has "As we may seo a wynter, isykles in euesynges". That dates from around 1390, if my memory is not playing tricks.
Rereading Seamus Heaney's The Midnight Verdict recently, I got to wondering about his good northern word slabber, verb and noun. We'd use slobber in the south, but I've heard slabber, to dirty with mud, in south-east Wexford, perhaps an import from England's West Country. Heaney's word means excessive guff, blather; his couplet is: Their one recourse is the licensed robber/With his legalese and his fancy slabber.
The primary meaning of slabber, verb, was to salivate excessively. In Yorkshire to slabber meant to wet the thread with spit in the process of spinning. It has a Dutch or German origin. Compare Dutch slabberen, Low German slabbern, to befoul with saliva. The compound bislabberen is found in Middle English.
The Wexford verb to slabber is from Middle Dutch slabber, muddy ground. Her milke pan and creame pot so slabbered and sost (dirtied)/That butter is wanting and cheese is halfe lost is from Tusser's Husbandrie of 1580.
Slobber, now standard English, is from the Dutch form slobberen.