Shudder
Middle English (as a verb): from Middle Dutch schūderen, from a Germanic base meaning ‘shake’.
wiktionary
From Middle English *shudderen, *schuderen (suggested by Middle English shuddering, schudering(“shaking, quivering, shuddering”)), from Middle Dutch schudderen and/or Middle Low German schodderen, [1] iterative forms of the verb at hand in Dutch schudden, Low German schüdden (both “to shake”), German schütten(“to pour”), from Proto-Germanic *skudjaną, from Proto-Indo-European *skewdʰ-. From Low German are also borrowed German schaudern(“to shudder”), Danish skudre.
etymonline
shudder (v.)
early 14c., possibly from Middle Dutch schuderen "to shudder," or Middle Low German schoderen, both frequentative forms from Proto-Germanic *skuth- "to shake." Related: Shuddered; shuddering.
shudder (n.)
c. 1600, from shudder (v.).