1. Good at remembering
   "tenacious memory"
   - retentive, recollective, long 
2. Stubbornly unyielding
   "a mind not gifted to discover truth but tenacious to hold it"; "men tenacious of opinion"
   - dogged, dour, persistent, pertinacious, unyielding 
3. Sticking together
   "tenacious burrs"
   - coherent

See also: adhesive, aware, mindful, obstinate, stubborn, tenaciously, tenaciousness, unregenerate

Encyclopedia: Tenacious

• silent picture
• silent treatment
• silently
• silents
• silenus
• silesia
• silex
• silhouette
• silica
• silica gel
• silicate
• siliceous
• silicic
• silicic acid
• silicide
• silicification
• silicify
• silicious
• silicle
• silicon
• silicon bronze
• silicon carbide
• silicon chip
• silicon dioxide
• silicon oxide