Modifiers matching reason:

• underlying,
• external,
• biological,
• academic,
• unknown,
• objective,
• personal,
• unavoidable,
• unforeseeable,
• practical,
• concrete,
• physical,
• economic,
• legitimate,

Simple categories matching legitimate:

• email,
• activity,
• industry,
• business,
• purpose,
• source,
• drug,
• job,
• struggle,
• case,
• expense,
• measure,
• action,
• discipline,
• organization,
• group,
• work,
• use,
• reason,
• enterprise,
• assessment,
• research,
• movement,
• profession,
• organisation,
• institution,
• chemical,
• interest,
• structure,
• location,
• outlet,
• agreement,
• relationship,
• goal,
• transaction,