"Study at old" could be replaced with several synonyms depending on the context and intended meaning. For instance, to "pursue higher education in advanced age", "continue learning in later years", or "attend university as an older adult" could be possible synonyms. Other options include "engage in lifelong learning", "undertake further education as a senior", "return to academia in later life", and "enroll in college as an older student". While some of these alternatives may differ slightly in definition, they share the same theme of older individuals choosing to continue their education.