Well,
go will make an adverb out of any adjective, but in this case it is more idiom than anything else.
leor is an adjective. It is usually used with
is, i.e.,
is leor ~ "it is enough ~"
go leor can function as an adjective (before or after a noun), or as a substantive, or as an adverb, and is usually used with
tá:
Tá daoine go leor ann. "There are enough/plenty/lots of people there."
Tá go leor daoine ann. "There are enough/plenty/lots of people there."
Tá go leor (de rud) agat. "You have plenty."
Tá go leor leor airgid aige. "He has lots and lots of money."
Tá go leor le rá aige. "He has a lot to say."
Tá sé mór go leor. "It is big enough/pretty big."
Maith is used on it's own attributively, i.e., directly modifying a noun, e.g.,
duine maith "a good person",
bean mhaith "a good woman".
When used predicatively,
maith is one of eight adjectives that always take
go as if they were adverbs:
Tá sé go maith. "He/it is good/well."
Tá sé go deas. "He/it is nice."
Tá sé go breá. "He/it is fine."
Tá sé go hálainn. "He/it is beautiful."Tá sé go hiontach. "He/it is wonderful."
Tá sé go haoibhinn. "He/it is pleasant."
Tá sé go dona. "He is bad."
Tá sé go holc. "He is wicked."
All adjectives in Welsh take a parallel particle
yn in the predicate. I am not sure if all adjectives used to take
go in the predicate in Irish or not.
Hope this helps.
