In QCD, there are quarks at high energies, and pions are composite degrees of freedom that appear at low energy where the quarks are strongly coupled. The pion Lagrangian is non-renormalizable; it breaks down at the QCD scale and must be replaced by the full UV-complete theory of QCD.
Are all effective field theories non-renormalizable quantum field theories which can nonetheless be used to make physical predictions at some energy scales because all but a small number of terms in the Lagrangian are suppressed at these energy scales?
Is the UV completion of a effective field theory a completely new quantum field theory? For example, is the lagrangian of QCD completely different in character than the pion Lagrangian, but reduces to the pion lagrangian at low energies?