1. Requiring great effort
   "a hard-fought primary"

See also: difficult, hard

• tetrahedral
• tetrahedrite
• tetrahedron
• tetrahydrocannabinol
• tetrahymena
• tetraiodothyronine
• tetralogy
• tetralogy of Fallot
• tetramerous
• tetrameter
• tetramethyldiarsine
• tetrametric
• Tetraneuris
• Tetraneuris acaulis
• Tetraneuris grandiflora
• tetranychid
• Tetranychidae
• Tetrao
• Tetrao urogallus
• Tetraodontidae
• Tetraonidae
• tetrapod
• Tetrapturus
• tetrarch
• tetrarchy