The term 'cause to grow thin or weak' can be broken down into four crossword solutions: MACERATE (8 letters), WASTE (5 letters), DEVELOP (7 letters), and RAISE (5 letters). MACERATE is a verb meaning to soften or break down by soaking in liquid, while WASTE is a verb meaning to use or expend carelessly, extravagantly, or to no purpose. DEVELOP is a verb meaning to bring out the capabilities or possibilities of, while RAISE is a verb meaning to cause to rise or increase. All four words can be used to describe the process of causing something to grow thin or weak.