帮忙 (bāng máng) means to help or lend a hand. 帮 means to assist and 忙 means busy/occupied work. The compound 帮忙 is used as a verb (来帮忙, come and help) or noun (谢谢帮忙, thank you for the help). A very common request is 帮个忙 (help me with something) or 请帮忙 (please help). It is similar to 帮助 (bāng zhù) but 帮忙 is more colloquial and emphasises the act of pitching in.