Publishing history:v1.0
v1.0: 01/10/24
feist 
Sometimes spelt feisd (e.g. MacLennan 1925; Faclan bhon t-Sluagh˄). An Stòr-Dàta 1993 gives fèist in error.
f. [feʃtʲ] 
Cf. /feʃdʲ/ (AFB˄).
and feiste -[ə], gen. feiste, ‘a tether rope’. McDonald (2009, 352) derives SG airfairste [sic], -faiste in the sense ‘anchored’ tentatively from ON festr [sic] ‘fast, fixed’, citing Craigie (1894, 156). Craigie’s own airfaiste ‘anchored’ is a typographical error for SG air feiste, a prepositional phrase meaning ‘tied by rope, tethered, anchored’, with feist(e) most probably from ON festi, accusative and dative of festr f. ‘rope, mooring line’.
Craigie cites the nominative festr. Jakobsen (1928) also derives Scots (Shetland) festa ‘a hook over the fire on which to hang a cooking-pot’ from ON festr. Angus Matheson (CG VI, 102) suggests that SG gearraiste [sic] ‘the part of a tether nearest the tether-stake’ consists of SG geàrr ‘short’ + feist ‘tether’, which he derives from ON festr.
SG feist(e) is associated with Lewis in Dwelly 1911 and Faclan bhon t-Sluagh˄ (s.v. feisd), but AFB˄ notes the term is also used in Tiree and Mull. The word is also found in the Mackay Country (North-West Sutherland) in the satirical song ‘Oran do Mhac-Culach’ by Rob Donn (1714–1778): Ged robh na ceudan turraban, | Ad chulaidh ’s i air faist, | ’S ann ortsa thig na pàisteachan, | Gu pàigheadh ’n airgid-bhaist (Mackay 1829, 119) ‘Although hundreds were fucking | Your piece tethered there 
Literally, ‘... your boat while it’s moored’. ‘The song to James MacCulloch ..., probably composed in the 1740s, concerns a forced marriage arranged by Lady Reay between her pregnant maid and the bard’s friend the weaver, who allowed himself to be entrapped in a compromising situation to provide a “screen for the sinners of the big house” ... Both Rob Donn and Rev. MacDonald [Murdo MacDonald, parish minister in Durness from 1726 until his death in 1763] formally rebuked all parties concerned, although the bard’s language was no doubt more sexually explicit ... In this case, Rob Donn considered his friend a victim and the woman a nymphomaniac, but this begs the question of the extent to which a young female domestic servant could resist the sexual advances of higher-ranking members and guests of the household and still retain her employment’ (Beard 2015, 146).
| You will be responsible for the children | When it comes to paying the baptismal fees’ (Grimble 1999, 193). Rob Donn’s editor (Mackay ibid., 354) provides the following gloss: ‘faist, air faist “acair, air acair, at anchor, moored” ’, and subsequently faist is relayed out of context as ‘faist “at anchor, moored” ’ in Dwelly 1911 and as ‘faist [fasht] “at anchor” ’ in MacLennan 1925.
AFB˄ gives air faist ‘fastenings’ its own entry; cf. faistichean, below.
Pace MacLennan, however, given the context of the stanza’s end-rhyming scheme (leisg : faisg : faist : -bhaist), Rob Donn’s faist is likely to have been pronounced feist [feʃtʲ] 
For the potential for [e] in words such as faisg and baist in the local Gaelic dialect, see Robertson (1907a, 94) and Grannd (2013, 12–13).
and is probably a reverse spelling on the analogy of (Mackay Country) faisg [feʃkʲ] etc.
In their own glossary, however, Gunn and MacFarlane (1899, 120) give ‘faist “at anchor, tied”; from the Eng. fast’.
The spelling air feist is itself found in Rob Donn’s song ‘Rann na Culaidh’ in Mac-an-Tuairneir 1813, 369 (also NLS Adv. MS 1669, folio 35r), with end-rhyme with aisd (i.e. aist(e) ‘out of it (fem.)’), locally [eʃtʲ].
AFB˄ lists SG faisteach f. /faʃdʲəx/ ‘fastening’, but this is a reconstruction from the plural form faistichean ‘fastenings’ recorded in South Uist (Faclan bhon t-Sluagh˄, s.v.), a form found also in the Tiree song ‘An Turus Cuain’: ’S a dh’fhuasgladh a cuid fhaistichean (Cameron 1932, 269) ‘and [when] her mooring lines were let slip’. Faistichean (pl.) is likely to be a variant of fastaidhean, plural of fastadh ‘mooring line’ (Campbell 1972, 116 
Which Campbell (p. 229) translates ‘warp, rope tying ship to pier’.
), which probably derives from Scots fast(a) ‘a rope fastened at either end to a large sunken stone and looped round the stem of a boat to serve as an anchor’ (SND˄, s.v. 2fast).
Ir. feiste f. ‘arrangement, adjustment, fastening’ and the verb feistigh ‘to arrange, adjust, trim; to fasten, secure; to moor’, vn feistiú, probably go back to MEng. feste ‘firm, fixed, secure (fast)’ (O’Rahilly 1913, 285–86).