definition from
Oxford Dictionary of English –

shrug /ʃrʌɡ /
▸ verb
(shrugs, shrugging, shrugged)
[with object] raise (one’s shoulders) slightly and momentarily to express doubt, ignorance, or indifference:
Jimmy looked enquiringly at Pete, who shrugged his shoulders
[no object] he just shrugged and didn’t look interested.
▪ (shrug something off) dismiss something as unimportant:
the managing director shrugged off the criticism.
▸ noun
1 an act or instance of shrugging one’s shoulders:
she lifted her shoulders in a dismissive shrug.
2 a woman’s close-fitting cardigan or jacket, cut short at the front and back so that only the arms and shoulders are covered.
– ORIGIN late Middle English (in the sense ‘fidget’): of unknown origin.