The verb "to two-time" is a 20th-century American colloquialism formed by combining the cardinal number "two" with the noun "time." The logic is transparently metaphorical: to engage in a romantic or deceitful activity with a second party, thereby allocating one's "time" to two different people simultaneously. It extends the concept of "double-crossing" or "playing both sides" from general deceit into the specific realm of infidelity. The construction follows a pattern similar to other verb phrases using numbers, such as "double-cross," reinforcing the idea of duplicity through simple, numerical imagery.

Structure: two + time - two: From Old English twā, meaning the number 2. In this compound, it signifies duality or double-dealing. - time: From Old English tīma, meaning a period or occasion. In this compound, it functions as a verb-forming element, implying an action performed on multiple occasions or with multiple parties.