constitutional (n.) Look up constitutional at Dictionary.com
"a constitutional walk," 1829, probably originally among university students, from constitutional (adj.) in the "beneficial to bodily health" sense.
constitutional (adj.) Look up constitutional at Dictionary.com
1680s, "pertaining to a person's (physical or mental) constitution," from constitution + -al (1). Meaning "beneficial to bodily constitution" is from 1750. Meaning "authorized or allowed by the political constitution" is from 1765. Constitutional monarchy is recorded from 1801, from French. Related: Constitutionally.