Complete opposites

While your dictionary or thesaurus may list a pair of words as antonyms, there’s a chance they really aren’t diametric opposites. For example, the opposite of cold is hot, not warm. Before you drop a word in as an antonym, look beyond the first definition and think about precisely what you want to convey.
Watch out for these 70 words and phrases that you’re probably using all wrong.
Useless/operative

Something can be useless for a particular task even while it is fully operative, aka, functioning, or in working order. Useful is the best word to express the opposite of useless. Example: New batteries made the television remote operative but it was completely useless as a hairbrush.
Worthless/adequate

Since worthless means of no value, its antonym is of great merit or value, not just passable or adequate. Example: The barren tree was worthless as shelter from the rain but the abandoned shed provided adequate cover for a while.