Is loimm de romuir.

Is loimm de romuir.

(tis * mouthful * of * great-sea)

It's a (mere) mouthful of the great sea.

In other words, it is just a tiny sample of what is out there. This image, which appears in stanza 41 of the Epilogue of Félire Óengussa, was apparently popular in Early Irish literature. It also shows up in "The poems of Blathmac, son of Cú Brettan", as edited and translated by David Stifter in installments on Twitter:

Ní mó bith loim de lir lán
nó do balcbúain barrgabál.

It is no more than a draught from a full sea
or taking a handful from a strong harvest.