1.
synonyms for future reference: swerve, depart, deviate, digress, diverge, stray, veer - These verbs mean to turn away from a straight or prescribed course: a gaze that never swerved; won't depart from family traditions; deviated from the original plan;
digressed from the main topic; opinions that diverged; strays from the truth; a conversation that veered away from sensitive issues. [AHD]
2. pairwise(!?) words
ravel : unravel
flammable : inflammable
regardless : irregardless
loosen : unloosen
generally, affixing in- or un- or dis- in the
completely sense makes them stronger than the original; e.g., annul and disannul.
