Merry UNDERTAKING is a phrase that can be used to describe a lighthearted or humorous TASK. The term is made up of two words, 'MERRY' and 'UNDERTAKING, ' which can be found in the crossword solutions LARK (4 letters) and TASK (4 letters). LARK is a verb meaning to engage in lighthearted or humorous activities, while TASK is a noun meaning an assigned job or duty. Together, these two words form the phrase MERRY UNDERTAKING, which can be used to describe a fun or amusing TASK.