Anyhow means in any case, or in a careless way. Anyhow, we left, do it anyhow, thrown down anyhow.
As a discourse marker it returns to the main point after a digression, which is the same job as anyway and slightly more informal. The other sense means without care: things left all anyhow. Note that the word is any plus how, built like somehow.
1adverbanyhowIn any case.
“It was raining, but we went for a walk anyhow.”
2adverbcarelessIn a careless way.
“The clothes had been thrown into the suitcase anyhow.”
anyhow is a connecting word.
Any plus how, built on the same pattern as somehow and anyway.
From any + how. From any + how.
Etymology from Wiktionary, CC BY-SA