I. noun
Date: 14th century
1. : the action of using one's mind to produce thoughts
2.
a. : opinion , judgment
I'd like to know your thinking on this
b. : thought that is characteristic (as of a period, group, or person)
the current student thinking on fraternities
II. adjective
Date: 1674
: marked by use of the intellect : rational
thinking citizens
• think·ing·ly adverb
• think·ing·ness noun