The term 'It's a Stunner' can be solved by two crossword solutions: TASER (5 letters) and PHASER (6 letters). A Taser is an electroshock weapon that uses electrical current to disrupt voluntary control of muscles, causing 'neuromuscular incapacitation'. It is often used by law enforcement as a non-lethal method of subduing a suspect. A Phaser is a fictional directed-energy weapon featured in the Star Trek universe. It is used to stun or kill targets by emitting a beam of energy.