impulsive

She is impulsive in her actions.

such impulsive acts as hugging strangers; impulsive generosity.See Synonyms at spontaneous

they had married as young impulsive teenagers.

perhaps he's regretting his impulsive offer.

The rumor had its origin in an impulsive remark.

Letting her friend borrow her car was an impulsive act that she immediately regretted.

When he had reached the upper landing an impulsive sidewise glance assured him, more clearly than before, of her uncommonly prepossessing appearance.