penetrate.1v.tr. aPollaim. The bullet penetrated the door, chuaigh an piléar tríd an gcomhla. bTreánn. To penetrate a secret, fios rúin a aimsiú; dul amach ar rún. To penetrate s.o.'s mind, léargas grinn a fháil ar intinn duine. 2v.i.The bayonet penetrated to the heart, chuaigh an beaignit go croí ann. The water is penetrating everywhere, tá an t-uisce ag púscadh isteach i ngach uile áit. To penetrate into a forest, bealach a dhéanamh isteach i ndiamhair choille.