Synonyms of clunky

2 Syllables
clunker, stumbling, bumbling, bungling, klutzy, inept, halting, gauche
3 Syllables
lumbering, floundering, graceless, inexpert, blundering, unhandy, unskillful, galumphing, maladroit
4 Syllables
ungraceful, cumbersome, heavyhanded, heavy-handed