The term 'knock one's socks off' is an idiom that means to surprise or impress someone greatly. The crossword solutions for this term are STAGGER (7 letters), AWE (3 letters), and STUN (4 letters). STAGGER means to move unsteadily, as if about to fall, while AWE is a feeling of reverential respect mixed with fear or wonder. Finally, STUN means to render someone unconscious or unable to move. All three words can be used to describe the feeling of being overwhelmed by something unexpected.