(UK, dialectal) A friend at one's back; a backer; one who does his best for another; a supporter.
(UK, dialectal) A hangnail.
(UK, dialectal, obsolete) A false friend; a secret enemy.
flanderkin
jackknifed
jackknifed
verb
simple past tense and past participle of jackknife
knifeboard
knifeboard
noun
(historical, by extension) An early bus with narrow, restrictive seating; a knifeboard bus.
(historical, chiefly attributive) A way of arranging benches back to back, resembling a knifeboard; common on the open upper deck of early double-deck omnibuses and trams.