capio

Capio, capere, cepi, captum. It belongs to the third conjugation, not the fourth, however much capio and capiunt look like audio and audiunt: the giveaway is the infinitive capere with a short e. This -io subgroup also holds facio, iacio, fugio and rapio, and they all behave the same way.

The perfect lengthens the stem vowel instead of adding anything, cepi, and the compounds weaken the a to i or e: accipio, recipio, incipio, excipio, percipio, decipio. Consilium capere is to form a plan, not to take advice; capere also covers holding in the sense of capacity, so a room capit so many people. English gets capture, captive, capable, capacity, and through the compounds accept, receive, deceive, perceive and except.