Constable

Constable was an unofficial title or affectionate nickname for Odo, the chief of security aboard Deep Space 9 (formerly known as Terok Nor).

A constable was a type of law enforcement officer as opposed to a military rank. Kira Nerys first used this nickname when she met Odo in 2365. Garak was the last to use this nickname. 

Odo's mentor Doctor Mora Pol took note of Commander Benjamin Sisko's calling Odo "Constable". Odo described it as "a nickname that I barely tolerate," but Mora pointed out that it was more than that, calling it an "expression of affection that you find uncomfortable."