Investigational rhymes with:
congregational, navigational, aberrational, coeducational, computational, conformational, confrontational, congregational, connotational, conversational, denominational, educational, foundational, generational, gravitational, improvisational, informational, inspirational, intergenerational, invitational, motivational, navigational, occupational, operational, organizational, recreational, relational, representational, rotational, sensational, situational, transformational, vocational