Clue: Tenser, quaking, about war god with cleaver, new (13)
Answer: ETRSTYRAXENNE
Explanation: Definition: Tenser, quaking, about war god with cleaver, new
***(tenser) **[anag:*quaking*] *about* **TYR** (a Norse "god") *with* **AXE** ("cleaver") + **N** (new) 
**ETRENNE*** (New Year's "gift") about ***STYRAX*** (a tropical and subtropical "tree")