In 1984, "ownlife" is the word for solitude. It means wanting to do your own thing, separate from communal Party activities. As the novel explains, every moment a Party member is not working, sleeping, or eating, he or she is supposed to be involved in a communal activity. For a Party member, even taking a walk alone is suspect. The government considers it dangerous, odd, and individualistic to be by oneself.
In our world, "ownlife," which implies living your own life on your own terms, is a positive way of being, one many people aspire to. But in Oceania it is a borderline illegal activity, the kind of behavior that can get a person noticed and in trouble with the Thought Police. Therefore, when Winston decides to wander around London by himself on a warm April evening rather than go the "Centre" and drink gin with other Party members, it is no wonder he thinks about "ownlife" and the risky path he is taking.