tropism (n.)

• affinity
• aptitude
• aptness
• bent
• bias
• cast
• delight
• diathesis
• disposition
• eagerness
• inclination
• leaning
• liability
• liking
• penchant
• predilection
• predisposition
• prejudice
• probability
• proclivity
• proneness
• propensity
• readiness
• susceptibility
• tendency
• turn
• twist
• warp
• weakness
• willingness