Very serious (Books)
Srimad-Bhagavatam
SB Canto 1
SB 1.18.49, Translation and Purport:
The sage thus regretted the sin committed by his own son. He did not take the insult paid by the King very seriously.
The whole incident is now cleared up. Mahārāja Parīkṣit's garlanding the sage with a dead snake was not at all a very serious offense, but Śṛṅgi's cursing the King was a serious offense. The serious offense was committed by a foolish child only; therefore he deserved to be pardoned by the Supreme Lord, although it was not possible to get free from the sinful reaction.