Here are some synonyms and alternative words for "however" , depending on the context:

As a conjunction (to show contrast)

• But
• Yet
• Nevertheless
• Nonetheless
• Still
• Although
• Though
• Even so
• On the other hand
• Conversely

As an adverb (to mean "in whatever way" or "to whatever extent")

• No matter how
• In whatever way
• To whatever extent

If you want, I can also provide example sentences for each usage!