soph·o·mor·ic
\ˌsäf-ˈmȯr-ik, -ˈmär- also ˌsȯf- or ˌsä-fə- or ˌsȯ-fə-\
adjective
: having or showing a lack of emotional maturity : foolish and immature
Full Definition
1 :conceited and overconfident of knowledge but poorly informed and immature <a sophomoric argument>
2 :of, relating to, or characteristic of a sophomore <sophomoric humor>