The Vietnamese phrase "cai đầu dài" literally translates to "long-headed guy" but is commonly used to refer to a "knavish contractor." This term usually describes someone in the construction or contracting business who is dishonest or untrustworthy, often engaging in deceitful practices to make money.
In more advanced discussions, you might use "cai đầu dài" when talking about the ethics of the construction industry or when discussing issues like corruption in business practices. It could be part of a larger conversation about consumer rights and the importance of hiring reputable contractors.
While "cai đầu dài" specifically refers to dishonest contractors, "cai" can also mean "to lead" or "to manage" in different contexts. "Đầu dài" on its own can refer to someone who is considered clever or crafty, but not in a positive way.