To move in a quick, fluttering, or hovering manner; to flutter about restlessly.
Possibly from flit combined with flutter or shudder, or from Low German/Dutch dialect roots related to fluttering motions; an uncommon or archaic English word with uncertain etymology, possibly dialectal.
Flidder is one of those wonderfully obscure English words that exists in some dictionaries but has almost disappeared from living speech—it's the kind of word that deserves revival because it captures a specific type of nervous, hovering motion.
Complete word intelligence in one call. Free tier — 50 lookups/day.