List of 426 Sets of Synonyms - How they Differ - Total of 2307 Words - 369

SYNONYMS: spontaneous, impulsive, instinctive, involuntary, automatic.
These adjectives mean acting, reacting, or happening without apparent forethought, prompting, or planning.

Spontaneous applies to what arises naturally rather than resulting from external constraint or stimulus: The two suddenly embraced in a spontaneous gesture.
Impulsive refers to the operation of a sudden urge or feeling not governed by reason: Letting her friend borrow her car was an impulsive act that she regretted.
Instinctive implies behavior prompted by instinct as a natural consequence of membership in a species: Nor is head-hunting, body-snatching, or killing for food instinctive or natural. The term also applies to what reflects or comes about as a result of a natural inclination or innate impulse: Offering to help the accident victims seems as instinctive as breathing.
Involuntary refers to what is not subject to the control of the will: Becoming a hero was involuntary. They sank my boat.
Automatic suggests the unthinking, unfeeling functioning of a machine; it implies an unvarying mechanical response or reaction: She accepted the subpoena with an automatic "thank you."