Definition of constitutional adjective from the Oxford Advanced Learner's Dictionary
constitutional
adjective
ˌkɒnstɪˈtjuːʃənl ˌkɑːnstəˈtuːʃənl
1[only before noun]connected with the constitution of a country or an organizationconstitutional government/reforma constitutional amendment2allowed or limited by the constitution of a country or an organizationThey can't pass this law. It's not constitutional.constitutional rightsa constitutional monarchy(= a country with a king or queen whose power is controlled by a set of laws and basic principles)
Opposite
unconstitutional3[usually before noun]related to the body's ability to stay healthy, be strong and fight illnessconstitutional remediesconstitutionally
ˌkɒnstɪˈtjuːʃənəli ˌkɑːnstəˈtuːʃənəli
adverbconstitutionally guaranteed rightsHe was much weakened constitutionally by the disease.