ONlwSG

dèilig m. [ˈd̥ʲe:liɡ̊ʲ], 

Cf. /dʲeːlɪgʲ/ (AFB^˄).

gen. dèilige -[ə], ‘dealing, intercourse, business’ 

Cf. AFB^˄: ‘dealing(s); small amount/portion’.

is derived by Mackay (1897, 92) from Ice. dael liki (leg. dæl-leiki (Cleasby 1874, s.v. dæl-leikr), cf. ON dælleikr (NO)) ‘familiarity, easy dealing’. McDonald (≈2009, 351) considers this unlikely, as it is ‘[l]ikely palatalised initial d- in Scottish Gaelic does not match Old Norse initial (non-palatal) d-.’ However, ON dæ- would formally yield SG [d̥ʲɛ:] with a palatalised dental, regularly. On the other hand, MacBain (1896; 1911, s.v. déilig) derives both SG dèilig the noun and dèilig the verb ‘to deal (with)’ from Eng. dealing – so also MacLennan (1925, s.v. déilig vb) – and this, or a loan from Scots deling, deil(l)ing (SND^˄), seems probable.

Ir. déileáil (deighleáil) vb ‘to deal’ and déileáil (deighleáil) vn (Ó Dónaill 1977) are presumably based on Eng. deal.

HSS (1828) lists both the noun and verb dèilig, and the derivative verbal noun dèiligeadh m., gen. dèiligidh, ‘dealing, transacting business, treating with one’, associating them with the North Highlands. Although usage seems to be have been generally more widely spread during the 19th century (as dèilig the verb and dèiligeadh are today), dèilig the noun appears to have become relatively uncommon by the mid-20th century (DASG^˄, s.v. d(h)e/é/èilig(eadh)), although it is still found in the genitive as the adjectival element in luchd-dèilige (An Stòr-Dàta 1993, s.v. client; MacDonald 1927, 29: luchd-déilig [‘customer’] 

Leis cho beulach ’s a tha an gille-bùtha, tha e a’ tarraing mòran luchd-dèilig thuige (≈ibid.) (‘the chattier the shop assistant, the more customers he attracts’).

), although this is more commonly luchd-dèiligidh today (e.g. Robertson and MacDonald, s.v. client; AFB^˄).