'Rackle', aside from being an anagram of 'Clarke', is a word of vague etymology (at least in terms of what's available on the web through a basic search).
Of Scottish origin (my ancestors were primarily Irish, English and Welsh, but an Irish great grandfather was born in Scotland), it has various meanings, such as 'impetuous', 'headstrong', 'fearless' or 'rash'.
There's some irony here, since I'm not an especially gregarious person, but I am headstrong (determined? persistent? patient? not easily swayed or duped?) in my own thoughtful way.