Causing a lot of disagreements or strong opinions.
"The new policy on climate change has been extremely controversial, sparking debates across the political spectrum."
Intimidating or frightening.
"Facing the vast, daunting mountain, she took a deep breath before starting the long ascent."
Causing great damage or suffering.
"Ignoring the evacuation warnings proved to be disastrous for the coastal town hit by the hurricane."
Too great to be overcome.
"Despite the team's best efforts, they found the challenge to be insurmountable."
Continuing to happen or develop.
"The ongoing construction of the new highway has caused regular traffic delays."
Spreading through and affecting every part of.
"The pervasive influence of social media is evident in nearly every aspect of modern life."
Causing difficulties or issues.
"The company's disregard for environmental regulations is becoming increasingly problematic."
Happening now; also describes a flow of water, air, or electricity.
"The hikers found it difficult to cross the river due to the strong current."
Having elements closely packed together.
"The dense forest made it challenging to navigate even during the day."
Very cold.
"Despite wearing several layers, the freezing temperatures made my morning walk extremely challenging."
Having a lot of weight; also can mean intense or severe.
"The heavy snowfall overnight has caused significant delays in public transportation."
Lasting for a long time.
"Investing in your education will have long-term benefits for your career and personal growth."
Originating from a particular place.
"The baobab tree is native to many African countries and is known for its massive trunk and long lifespan."
Not affected or harmed by something.
"The bacteria have become resistant to this antibiotic, rendering it ineffective."
Very bad, serious, or unpleasant.
"The doctor warned that not following the treatment could lead to severe complications."
Coming in a fast, overwhelming manner, usually used to describe rain.
"The torrential downpour lasted for hours, causing the city streets to flood rapidly."
Hot and humid, like the climate near the equator.
"During the winter months, many people crave a getaway to tropical destinations where the sun kisses their skin and the sea breeze refreshes their spirit."
Having no net carbon dioxide emissions.
"The company has implemented various environmental initiatives to become completely carbon neutral by 2030."
Good for the environment.
"Many consumers are now looking for eco-friendly products to reduce their environmental impact."
Able to be recharged and used again.
"I always use rechargeable batteries in my camera to reduce waste and save money."