These words sound similar, and over time their meanings have come to overlap somewhat. Generally, however, they are regarded as having different meanings and uses—although the differences are admittedly subtle—and in choosing between them, writers should carefully consider the message they wish to convey.
Purposely—meaning “with a deliberate or express purpose”1 or “intentionally”2—was first on the scene, entering usage in the late 1400s.2 A second meaning, “to good purpose; effectively,” came into use about 100 years later but is now considered obsolete.2
In contrast, purposefully—meaning “full of determination”1—was a relative latecomer, not coming into use until the mid 1800s,2 and is still used in those senses. Over time, though, purposefully also has come to be used interchangeably with purposely in the sense of “intentionally,”2 perhaps because something done with determination is also done intentionally. But of course the reverse is not necessarily true, which suggests that writers should use purposely when referring to intention alone.
To some ears, however, purposely sounds uneducated or incorrect, leading some writers to instead use purposefully in error; moreover, writers simply looking for a more impressive word will also sometimes instead use purposefully—again incorrectly.3 But even when purposefully is the correct choice, writers should take care that their intended meaning is not misconstrued. For example, the statement “On occasion, a clinician might purposely elicit pain” likely simply means that the clinician is intentionally eliciting pain (for the purpose of making a diagnosis). On the other hand, the statement “On occasion, a clinician might purposefully elicit pain” might imply that the clinician is determinedly eliciting pain (again—one can only hope—for the purpose of making a diagnosis). In both instances, careful handling of the context can make clear that the elicitation of pain is a necessary evil in service of a worthy end. For example, simply ending either of the above statements with “to help make a diagnosis” can go a long way toward ensuring that the clinician is not construed as something of a sadist.
The bottom line:
●Is “intentionally” the intended message? Use purposely.
●Is “full of determination” the intended message? Use purposefully.
●In both cases, however, take care to ensure that the context helps readers determine the intended meaning.—Phil Sefton, ELS
1. Merriam-Webster’s Collegiate Dictionary. 11th ed. Springfield, MA: Merriam-Webster Inc; 2003:1011.
2. The Compact Oxford English Dictionary. 2nd ed. Oxford, England: Oxford University Press; 1991:1474.
3. Purposefully, purposely. In: Bernstein TM. The Careful Writer: A Modern Guide to English Usage. New York, NY: Athaneum; 1985:376.