Catalyzes the hydrolysis of endogenous amidated lipids like the sleep-inducing lipid oleamide ((9Z)-octadecenamide), the endocannabinoid anandamide (N-(5Z,8Z,11Z,14Z-eicosatetraenoyl)- ethanolamine), as well as other fatty amides, to their corresponding fatty acids, thereby regulating the signaling functions of these molecules (PubMed:17015445, PubMed:19926788). Hydrolyzes monounsaturated substrate anandamide preferentially as compared to polyunsaturated substrates. {ECO:0000269|PubMed:17015445, ECO:0000269|PubMed:19926788}. This is the function of Ensembl gene identifier ENSG00000165591 (FAAH2, fatty acid amide hydrolase 2).