Category Nuances for caffeine:

• addictive,
• common,
• unhealthy,
• soft,
• nonpolar,
• mild,
• interfering,
• anthropogenic,
• behavioural,
• costly,
• toxic,
• psychoactive,
• harder,
• related,
• bitter,
• organic,
• stimulating,
• irritating,
• active,
• legal,
• interactive,
• aromatic,
• desirable,
• sympathetic,
• numerous,
• recreational,
• pharmacological,
• harsh,
• familiar,
• everyday,
• up,
• unwanted,
• valuable,
• harmful,
• illegal,
• model,
• bad,
• neutral,
• undesirable,
• polar,
• off,
• potent,
• nonvolatile,
• popular,
• diverse,
• noxious,
• threatening,
• allergenic,
• inert,
• volatile,
• secondary,
• aversive,
• psychotropic,
• molecular,
• benign,
• chemical,
• pure,
• dangerous,
• licit,
• harmless,
• pharmaceutical,
• nonprescription,
• major,
• salty,
• available,
• urban,
• lipophilic,
• alkaline,
• simple,
• herbal,
• miscellaneous,
• good,
• soluble,
• particular,
• counter,
• unacceptable,
• nitrogenous,
• exogenous,
• basic,
• noninvasive,
• natural,
• important,
• external,
• dietary,
• additional,
• functional,
• innocuous,

Simple Categories for caffeine:

• material,
• substance,
• compound,
• solute,
• contaminant,
• change,
• matter,
• precursor,
• measure,
• system,
• constituent,
• thing,
• item,
• component,
• chemical,
• fluid,
• attribute,
• heterocycle,
• xanthine,
• preparation,
• alkaloid,
• particle,
• activator,
• solid,