Cessna 140 pilot reported a ground conflict during taxi requiring immediate braking action to avoid a possible collision. The tail of the aircraft lifted during the braking action causing the propeller to strike the ground and the engine to subsequently seize.

Narrative

Landed Runway XX and exited the runway at [Taxiway] 1. Advised Tower that I was to taxi back and depart using the ZZZZZ departure. Tower directed me to taxi via Taxiway 2 to the departure end of Runway XX and to stay on Tower frequency. As I taxied abeam the FBO the school aircraft departed the ramp area on to the taxiway feet in front of me. Immediate and aggressive braking was required to not make contact. As the Cessna 140 is a tailwheel the tail rose and the prop struck the ground. The engine stopped. I shutdown the aircraft and assessed the other crew's physical status. The Instructor Pilot said that he was cleared to taxi but delayed after the clearance and did not advise Ground. I had no idea that the aircraft was cleared to taxi as I was on Tower frequency. I did not receive an advisory to look for traffic from the ramp. As I came to a stop I noticed that the IP (Instructor Pilot) was not looking my direction. He came to me and admitted that he was cleared to taxi but failed to heed the clearance in suitable time. He also 'did not see me until the student pulled out'. Occurrence cause: failure of the incurring aircraft from the ramp to the active taxiway to give way to my aircraft established and cleared on the taxiway. Contributing factors: 1. Tower kept me on Tower frequency decreasing my situational awareness of the taxi environment; 2. Instructor Pilot distraction from the situation; 3. Difficulty in Tower's ability to see the busy FBO ramp and to monitor aircraft entering the taxiway; 4. Failure of the PIC (Pilot in Command) of the incurring aircraft to advise Ground that he was not able to meet ground instruction in a timely manner.