conk – Slang term for a big nose. The term Old Conky was a nickname for the Duke of Wellington. Dinneen gives coinncín as "a prominent nose" and this seems to be related to terms like geanc, meaning a snub nose.
coshering – Nothing to do with Jewish dietary law. Coshering (from Irish cóisir, feast) was when a lord went round staying with his subjects and expecting to be entertained. Because of this cóisireacht can mean "sponging" in Modern Irish, though cóisir usually just means a party.
coyne – A kind of billeting, from Irish coinmheadh.
crock – As in 'A crock of gold', from Irish cnoc.
cross – The ultimate source of this word is Latin crux. The English word comes from Old Irish cros via Old Norse kross.
Limerick – (from Luimneach). The limerick form was particularly associated in the 18th century with a group of Irish language poets called Filí na Máighe.
puck – (in hockey) Almost certainly from Irish poc, according to the OED.
puss – As in sourpuss, comes from Irish pus, a pouting mouth.
rapparee – An Irish highwayman, from ropaire (a stabber)
rath – A strong circular earthen wall forming an enclosure and serving as a fort and residence for a tribal chief. From Irish rath.
shamrock – (from seamróg) a shamrock, diminutive of seamair, clover, used as a symbol for Ireland.
Shan Van Vocht – (from seanbhean bhocht meaning "poor old woman") a literary name for Ireland in the 18th and 19th centuries.
shebeen – (from síbín meaning "illicit whiskey, poteen", apparently a diminutive of síob, which means drift, blow, ride) unlicensed house selling alcohol (OED).
shillelagh – (from sail éille meaning "a beam with a strap") a wooden club or cudgel made from a stout knotty stick with a large knob on the end.
shoneen – A West Brit, an Irishman who apes English customs. From Irish Seoinín, a little John (in a Gaelic version of the English form, Seon, not the Irish Seán).
Sidhe (Modern Sí) – the fairies, fairyland.
slauntiagh – An obsolete word for sureties or guarantees, which comes from Irish sláinteacha with the same meaning.
sleeveen, sleiveen – (from slíbhín) an untrustworthy or cunning person. Used in Ireland and Newfoundland (OED).
slew – (from slua meaning "a large number") a great amount (OED).
slob – (from slab) mud (OED).
slug – (from slog) A swig of a drink, e.g. A slug of red eye
smithereens – small fragments, atoms. In phrases such as "to explode into smithereens". This is the Irish word smidiríní. This is obviously Irish because of the –ín ending but the basic word seems to be Germanic, something to do with the work of a smith.
spalpeen – A migratory labourer in Ireland. From spailpín.
tanist – The deputy and successor of a chieftain or religious leader. A term used in anthropology. From Irish tánaiste, secondary person.
tilly – (from tuilleadh meaning "a supplement") used in Newfoundland to refer to an additional luck-penny. It is used by James Joyce in the first chapter of Ulysses.
tory – Originally an Irish outlaw, probably from the word tóraí meaning "pursuer".
turlough – A seasonal lake in limestone area (OED). Irish turloch "dry lake".
uilleann pipes – Irish bellows-blown bagpipes. uilleann is Irish for "elbow".
usker – From Irish uscar, a jewel sewn into an item of clothing.
whiskey – From uisce beatha meaning "water of life".
Other words:
Bualadh bos (A round of applause)
Camán (hurley)
Cipín (Small stick/firekindling)
Coláiste (College e.g. Coláiste Dhúlaigh College of Further Education)
Comhairle (Council e.g. An Chomhairle um Oideachas Gaeltachta & Gaelscolaíochta / COGG)
Crúibín (Pigs foot)
Fáilte (Welcome)
Fláithiúil (Excessively/uncommonly generous)
Grá (Great love or affection for someone/something)
Is maith liom (I like/It's good)
Lúdramán (Fool)
Lúdar (Fool)
Meas (High regard/respect for someone/something)
Óinseach (Fool, generally female)
Plámás (Excessive/Insincere praise or flattery)
Sceach (Any thorny bush, sceach gheal (Hawthorn))
Sláinte (Cheers|Good Health)
Slán (Safe, whole, healthy, complete) (Shortened version of go dté tu slán ("may you go safely"), used as modern equivalent of the French au revoir or English see you.)
^Complete Atlas of the British Isles. Reader's Digest. 1964. p. 142.