In Ua Laoghaire's Sermon for the Sunday after the Epiphany, I found this: A phobal Dé, is iúntach an teilgean atá i bhfoclaibh agus i gcainnt an tSoíscéil.

Teilgean: normally 'casting', but FGB also has 'economisation'.

I think this must mean that the words of the Gospel for that day are pithy. Guntacht is another way of saying this. Do people agree with my translation of pithiness?

Ó Dónaill has as a 6th (literary) meaning of teilg 'Cast in one’s mind, consider', which would be a similar idea to the abstract sense of 'reflect' in English. So maybe in this case then, teilgean means 'thought', 'reflection', 'consideration'.

This is the whole first paragraph:

A phobul Dé, is iongantach an teilgean atá i bhfocalaibh agus i gcaint an tSoisgéil. D'á fhaid agus d'á dhoimhne a dhéanfadh duine machtnamh ortha, agus d'á fhaid a bhéadh sé ag léiriughadh agus ag nochtadh a mhachtnaimh, ní bhéadh iomláine a mbríghe tabhartha leis aige. Is fearr, d'á bhrígh sin, greamughadh ar aon nídh amháin sa tSoisgéal, nó ar aon abairt amháin, nó ar aon fhocal amháin, agus taíghde air sin chómh fada agus is féidir é, 'ná bheith ag gluaiseacht tríd an Soisgéal go léir agus gan bheith ábalta ar dhul ró dhoimhinn i n-aon bhall ann.

I see what you're saying. 'Economisation' or 'pithiness' would seem to make more sense in this context.

Dinneen has "expression, utterance, eloquence, drift or import (of a story)"

Yes, so it could be eloquence?

Yes, or simply an expression.
The positive meaning is given by iontach:
teilgean iontach = "wonderful expression"

(BTW: It isn’t really far from the literal meaning as I had thought at first:
teilg < to-as-leig = "let out", as = ex = out, hence expression, e(=ex)loquence)

Thank. I didn't realise that was the etymology. The most common use is 'hurling, casting'.