老 (lǎo): A common character meaning “old” or “experienced.” It signifies a long time spent in a particular role or environment.
油 (yóu): Means “oil” or “grease.” Here, it carries the metaphorical sense of being “oily,” “slick,” or “slippery”—someone who is smooth and hard to get a grip on.
条 (tiáo): A measure word for long, thin objects. In this context, it completes the name of the food item, `油条`.
The characters combine to literally mean “old oil stick,” referencing the food. The term's genius lies in transferring the physical properties of an old, re-fried `油条` (tough, oily, unappetizing) onto the personality traits of a person who has become jaded and difficult through long experience.