In Portuguese, what is the etymology of ‘preciso’ as in ‘needing to do something’, e.g., “Eu preciso perdoar”?

Answer 1

I'm not sure the reason preciso means "need" can be traced for sure. When the common latin spread around the peninsular locals may have changed prefiro into preciso - but the real reason preciso has its particular meaning may not have a clear solution. Spanish necesito may have also evolved into preciso.

Answer 2

Required; indispensable.