As a comparative form, older would logically seem to indicate greater age than old. Except when a direct comparison is being made, however, the opposite is generally true. The older man in the tweed jacket suggests a somewhat younger man than if you substitute old. Where old expresses an absolute, an arrival at old age, older takes a more relative view of aging as a continuum—older, but not yet old. As such, older is not just a euphemism for the blunter old but rather a more precise term for someone between middle and advanced age. And unlike elderly, older does not particularly suggest frailness or infirmity, making it the natural choice in many situations.
