Is it even a legit word?
Well, Tom, it is a real word - at least it's in the COD, meaning (a) 'of or appropriate to a painter' or (b) 'demonstrating effective use of paint'.
The problem, it appears to me, is that it still doesn't really seem to mean much.
How to use it in a sentence?
How about '
Van Gogh painted in a painterly way.' Of course he did; he was a painter - one of the greatest the world has ever seen.
The M/W examples of '
painterly used in a sentence' are not much better:
'
He has a painterly eye.' and '
a painterly picture of the sea'
In short, I get the impression that it's a word the English Language could do without.
But wait; maybe, skulking in the darkest recesses of the OED, there are similar words, pertaining to the other arts -
How about
'Rodin sculpted in a
sculptorly way.'
'Nijinsky danced in a
dancerly manner.'
'Caruso sang in a
singerly fashion.'
or even
'Miles Davis trumpeted in a
jazz-trumpeterly style'
I somehow suspect we won't be seeing any of these in a Chi game any time soon.