thanks a lot informal (also thanks a bunch American EnglishAmE spoken) used when really you are annoyed about something and you do not mean ‘thank you’ at all 谢谢你〔反语,表示对某事感到生气〕thanks a lot• "I forgot to bring your money." "Well, thanks a lot!"• Gee, thanks a lot for saving me from Madonna in the morning.• Hey, thanks a lot, Wyatt.
→ thanks a lot at thanks1(2)