1) ADJ: v-link ADJ, v n ADJ If something is afire or is set afire, it is on fire or looks as if it is on fire.

The houses were set afire but there were only minor injuries to seven personnel...

The sun has already set, leaving the sky afire with orange and green light.

2) ADJ: v-link ADJ, oft ADJ with n If someone is afire with emotion, they are extremely enthusiastic and excited about something. [LITERARY]

All Dan's senses were afire...

Sydney is afire with Olympic enthusiasm.

English dictionary. 2008.