The more usual spelling is Monier but here W W gill (www.manxnotebook.com/fulltext/scrap3/ch03.htm) comments on transformation which includes Macnameer:
MacNamaire occurs in Ballaugh Parish Register in 1822. This was MacGilmere and MacEmere in 1513 in the two adjoining parishes, and underwent many transformations until, as Monier (pronounced probably Moneer), it died out in the Island before the middle of the 19th century.
Kinvig in his article on Manx emigration (www.manxnotebook.con/iomnhas/v054p436.htm) has:
The name Monier (pronounced Mo-neer with the accent on the second syllable) which appears in this list is of especial significance since it provides an excellent example of a Manx surname which has become extinct in the land of its origin while it is relatively widespread in the United States. The name can be traced back to at least the early sixteenth century in the Island, being particularly associated with the parishes of Bride and Andreas. The name has disappeared in the Isle of Man since about 1860, and one of the last families to bear it was that of William Monier, who had been a miller at the Dog Mill near Ramsey. In 1850 he left the Island with his wife, Jane Quayle, and their eight children to settle in Peoria, and descendants of that family consisting of the third, fourth and fifth generations, are settled over the United States from South Carolina through Illinois to California.
He refs an article by Cubon in J Manx Mus - unfortuneately I don't seem to have a copy nor of the also reference NAMA bulletin