hard·hat or hard-hat 
(härdhăt′)
(härdhăt′)n.
1.
a. A lightweight protective helmet, usually of metal or reinforced plastic, worn by workers in industrial settings.
b. Informal A construction worker.
2. Slang
a. An ultraconservative.
b. An extremely patriotic person with a conventional, usually unquestioning sense of morality.
adj.
1. Relating to heavy industry, construction, or demolition.
2. Informal Of, relating to, or characterized by extreme conservatism.
3. Slang Extremely patriotic.