| Answer | Crossword Clue |
|---|---|
| SNAKE | Insidious villain |
| SLY | Insidious |
| EVIL | Insidious |
| SNARY | Insidious. |
| SUBTLE | Insidious |
| WEASEL | Insidious one |
| SLIER | More insidious. |
| COBWEB | Insidious snare |
| SNAKES | Insidious sorts |
| SNARY | Entangling; insidious |
| JUDAS | Insidious betrayer |
| SNAKE | Insidious sort |
| SLYEST | Most insidious |
| SNARY | Entangling; insidious. |
| PLOT | Insidious scheme |
| BENEDICT | Insidious Arnold |
| SNAKE | Insidious one. |
| GUILE | Insidious cunning. |
| SLYER | More insidious |
| SAXROHMER | Creator of the insidious Fu-Manchu. |
| TROJANS | Insidious malware with a classically derived name |
