Green’s Dictionary of Slang

dozer n.

[SE doze]

(Irish) a slow-witted person; usu. as no dozer.

[[UK]Scots Mag. 5 June 37/2: The Dozer [...] is none of your flashy aetheistical wits].
[Ire]J. Morrow Confessions of Proinsias O’Toole 28: As you request, I’ll zoom to the point ... Francie O’Fallis, you are no dozer.
[Ire]Irish Indep. 21 Dec. n.p.: No dozer when it comes to spotting a good yarn [BS].