Punt is often used to describe the action of moving a packet from the fast path (CEF) to the route processor for handling.
Cisco Express Forwarding (CEF) provides the ability to switch packets through a device in a very quick and efficient way while also keeping the load on the router`s processor low. CEF is made up of two different main components: the Forwarding Information Base (FIB) and the Adjacency Table.
Process switching is the slowest switching methods (compared to fast switching and Cisco Express Forwarding) because it must find a destination in the routing table. Process switching must also construct a new Layer 2 frame header for every packet. With process switching, when a packet comes in, the scheduler calls a process that examines the routing table, determines which interface the packet should be switched to and then switches the packet. The problem is, this happens for the every packet. Reference:
http://www.cisco.com/web/about/security/intelligence/acl-logging.html