Thick and slender are antonyms, words with opposite meanings.
antonyms for slender
They can be antonyms (opposite meanings), not synonyms.
antonyms
go on www.synonym.com 4 synonyms & antonyms
Antonyms: opposite. Synonyms: similar.
Synonyms: moving Antonyms: Fixed, Stationary
there is no synonyms or antonyms for convection current
Synonyms. Synonyms are words the same in meaning and antonyms are opposites
They are synonyms. Synonyms have similar meanings, antonyms have opposing meanings.
they are closer to synonyms than antonyms, although they are not direct synonyms.
Antonyms. Antonyms = Opposites Synonyms = Same Meaning