mad dog

Short definition from Wiktionary

Noun

1. 1
   A rabid dog.
2. 2
   Someone who is aggressive and fanatical; an aggressor who cannot be reasoned with.
3. 3
   A McDonnell Douglas MD-80 series aircraft.
4. 4
   Attributive form of mad dog
5. 5
   Alternative form of mad dog.

Adjective

1. 1
   Fanatically or irrationally ferocious.