Meaning of -IER in English
var. of -er 1 , usually in nouns designating trades: collier; clothier; furrier; glazier.
[ ME -ier ( e ), var. of -yer ( e ) (cf. -YER), equiv. to -i- v. stem ending + -ere -ER 1 , prob. reinforced by OF -ier -arius -ARY (cf. SOLDIER) ]
a noun suffix occurring mainly in loanwords from French, often simply a spelling variant of -eer , with which it is etymologically identical ( bombardier; brigadier; financier; grenadier ); it is also found on an older and semantically more diverse group of loanwords that have stress on the initial syllable ( barrier; courier; courtier; terrier ). Recent loanwords from French may maintain the modern French pronunciation with loss of the final r sound ( croupier; dossier; hotelier ).
[ -arius, -aria, -arium -ARY; cf. -AIRE, -EER, -ER 2 ]
Random House Webster's Unabridged English dictionary. Полный английский словарь Вебстер - Random House . 2012