tenacious
Cross references: 1. strong te.na.cious \t*-'na--sh*s\ aj [L tenac-, tenax tending to hold fast, fr. tene-re to hold] 1a: not easily pulled apart : COHESIVE, TOUGH {a ~ m etal} 1b: tending to adhere to another substance : STICKY {~ bur s} 2a: holding fast or tending to hold fast : PERSISTENT, STUBBORN {~ of his rights} 2b: RETENTIVE {a ~ memory} - te.na.cious.ly av