This is the 1882nd most frequent Arabic word.
سيئة
Bad deed or wrongdoing.
Here, 'سيئة' describes the quality of the experience, working as an adjective to exemplify negativity.
كانت التجربة سيئة للغاية.
The experience was very bad.
In this sentence, 'السيئ' (bad) modifies 'الأثر' (effect), serving as an adjective to characterize the noun.
أثره السيئ واضح للجميع.
Its bad effect is clear to everyone.
Here, 'السيئة' refers to a general negative deed or act, functioning as a noun to convey the idea of evil.