"Adze head" is an old poetical reference to St Patrick.
It is the word used to describe him in the Betha Phátraic (life of Patrick), found in mediaeval Irish manuscripts
1. Leabhar Breac "The speckled book"
2. Rawlinson B512
3. Egerton 93
It is used in context of a prophecy which sets the scene of druids or sages predicting the coming of "taillcend" (Adzehead).
This is a link to the University College Cork (UCC) CELT project website with the text translation of the Life of Patrick by Whitley Stokes (scroll down to p.19 for the prophecy but I copied text here in case you have problems with the link.
Patrick afterwards passed over sea to Ulster to seek Míliuc, King of Dalaraide, to preach the name of God, as it was with him he was in servitude at first, that it might be to him he should first preach, and the service to Míliuc's body and to his soul might thus be complete. Howbeit Míliuc came against him with great hosts of heathens, and would not let him land, since Loegaire had ordered the men of Ireland that they should not let Patrick on land: for his soothsayers had foretold to Loegaire, five years before, that Patrick would arrive in Ireland, to wit, Lochra and Lothrach and Luchatmael and Renell were their names, and this is what they used to say—
An Adzehead shall come across stormy (?) sea:
His mantle hole-headed, his staff crook-headed:
His dish in the east of his house:
All his people shall answer himAmen, Amen;
http://titus.uni-frankfurt.de/texte/etc ... /vitat.htm
(verse in Old Irish from the link above, my translation in brackets and comments * below)
Ticfa tailcend (The Aze head will come)
tar muir meircenn, (over the wild/raging sea *)
a bratt tollcend, (his mantle holeheaded **)
a chrand cromchend, (his staff bent-headed ie.crook'd - a crozier)
a mías i n-airthiur a tigi, (his altar*** in the east of his house)
fris[c]érat a muinter huili: Amen, Amen(all his people will respond "Amen")
meircenn/ meircend can be used to mean "crazy" or "demented" and can be used to describe the hero-rage that comes over a warrior, but it is also an allusion to the sea (a compound of mer and cenn). Its' often translated as "crazed in the head" in this verse but I think I'd attribute that "rage" to the sea he is crossing.
Toll means pierced/ hole/ perforated etc. but I'm not sure that is the literal sense here. There's an article in the journal Ériu if you have access to an academic library[Ériu xiii.141.20]. I need to look that up to see what else they give.
mías is a food slab, a wooden board, a tray or table but in the sense of a churchman, I think it's better translated as "his altar" ie. the altar in the eastern position in the church)