common sense (uncountable)

1. Ordinary sensible understanding; one's basic intelligence which allows for plain understanding and without which good decisions or judgments cannot be made.
   • 1776, Horace Walpole, Letter to Sir Horace Mann:

     To act with common sense, according to the moment, is the best wisdom I know; and the best philosophy, to do one's duties, take the world as it comes, submit respectfully to one's lot, bless the goodness that has given us so much happiness with it, whatever it is, and despise affectation.

2. (obsolete) An internal sense, formerly believed to be the sense by which information from the other five senses is understood and interpreted.
   • 1624, Democritus Junior [pseudonym; Robert Burton], The Anatomy of Melancholy: […], 2nd edition, Oxford, Oxfordshire: Printed by John Lichfield and James Short, for Henry Cripps, OCLC 54573970 ↗:

     , Book I, New York 2001, p.159:

     This common sense is the judge or moderator of the rest, by whom we discern all differences of objects; for by mine eye I do not know that I see, or by mine ear that I hear, but by my common sense […].

• (ordinary sensible understanding) cop on (Ireland, informal), good sense, mother wit, native wit

• French: bon sens, sens commun
• German: gesunder Menschenverstand
• Italian: buonsenso
• Portuguese: senso comum, bom senso
• Russian: здра́вый смысл
• Spanish: sentido común