"Gotten cold feet" is a common phrase used to describe a sudden loss of courage or a change of heart. However, there are plenty of other synonyms that can convey a similar sentiment. For instance, you might say someone "chickened out" or "backed down." Similarly, "reneged" or "retreated" could both be used to suggest a decision that involves "getting cold feet." Other options might include "wimped out," "pulled out," "flinched," or "backed off." Ultimately, the key is to choose a word or phrase that conveys the indecisiveness, nervousness, or fear that is typically associated with "getting cold feet".