ONlwSG

blog ?m. *[b̥ɫ̪ɔɡ̊] ‘clumsy fellow’ is cited by Henderson (≈1910, 206), who compares ‘the Norn blogg “big and clumsy”, from ON blokk, in blokkstor “enormously big”’. McDonald (2009, 343) points out that neither the Old Norse nor Scottish Gaelic form appears in the standard range of lexical works, and, noting MacBain’s (1911) derivation of SG ploc ‘clod, clump, lump’ from Eng. block, considers the loan unlikely.

EG pluc m. and pluic f. ‘distended cheek’ (from onomatopoeic use 

And of Germanic or Romance origin, cf. Fr. bloc, Germ. Bloch, Eng. block (Vendryes 1996, s.v. pluc).

) develops the sense ‘cheek’, hence ‘round mass, knob, lump; club’; hence SG pluc, pluic and the diminutives plucan, var. plugan, 

MacLennan 1925, s.v. plucan.

in the senses ‘cheek (usually pluic), and pimple, blister, lump, bump, the head of something (e.g. of a pin), knot, bung (usually pluc, plucan)’.

Although the sense ‘bung’ may owe something to Eng. plug, and although SND^˄ derives SG pluc in the sense ‘pimple’ from Scots plouk ‘pimple, knob’.

EG bloc, i.e. blocc, ‘block’ is from Eng. block (or Fr. bloc) (eDIL^˄); hence SG bloc and the diminutive blocan, and variants blog 

MacBain 1911, s.v. blocan; Dwelly 1911, with a cross-reference to blocan.

and blogan, 

Wentworth 2003, s.v. chopping-block.

and, later, bloca 

AFB^˄; with its homogenising final -a, common in English loans in Scottish Gaelic from original monosyllables in a final consonant, e.g. SG còta < Eng. coat, SG nota < Eng. note.

‘block; building block etc.’.

Meanwhile, Eng. or Scots block has also yielded SG ploc and the diminutive plocan, under which the senses of bloc(an) and pluc(an) have tended to fall together: ‘block; round mass, lump; clod, sod; block of wood, mallet, masher, club; bung; cheek’.

In Irish, the situation appears to be a little more straightforward: cf. (Ó Dónaill 1977) Ir. pluc f. ‘rounded cheek; bulge’, Ir. bloc, dim. blocán, ‘block’ and Ir. plog = pluga m. ‘plug’.

^,  

SND^˄ derives Scots plock ‘spar or block of wood’ from SG ploc.

Henderson’s SG blog in the sense ‘clumsy fellow’ seems likely to derive from OScots blok, block, bloke (cognate with Eng. block) in the figurative sense ‘blockish person; stumbling block’ (DOST^˄). Henderson’s Norn (Scots) blogg ‘big and clumsy’ is from Jakobsen (1928) and noted in SND^˄ and may simply be an adjectival use of OScots blok.

?Cf. ≈Lhuyd 1707, which gives ‘bloc uo [=no ‘or’] bloch, cruinn “round”’, which is perhaps an adjectival use of bloc, above. However, Shaw 1780 cites bloc ‘round’, while Armstrong 1825 gives †bloc ‘round’ (from English) and HSS 1828 †bloch (from Lhuyd).

The intensive prefix blokk- is unattested in Old Norse but found in modern usage in, for example, Nn. blokkstor ‘very big’ and Sw. blockstor, blokkstor, blåkastor (Torp 1991, s.v. blokk, who compares Jakobsen’s blogg adj.; SAO, s.v. block (5e, and blockstor)).