Some common synonyms for "however" as a conjunctive adverb expressing contrast include:

• Nevertheless
• Nonetheless
• Yet
• Though
• Although
• Notwithstanding
• Still
• Even so
• In spite of that
• Despite that
• Just the same
• Be that as it may
• Albeit

When "however" means "in whatever way" or "regardless of how," synonyms include:

• Any way
• Whichever way
• No matter how
• In any manner
• Regardless of how

These synonyms can often be used interchangeably with "however" depending on the sentence structure and context.