All 5 Uses of

however
in
Main Street, by Sinclair Lewis

This motto, however, they did not commend to farmer customers who had had crop failures.
Chpt 9 *

however = a word used to connect contrasting ideas as when using though, in spite of that, in contrast, nevertheless, etc.

However charitable toward the Lower Classes she may have thought herself, Carol had been reared to assume that servants belong to a distinct and inferior species.†
Chpt 9

She could rebel against the town's prying now that she had something, however indistinct, for which to rebel.†
Chpt 30

However inadequate the rest of the house, he had seen to it that the fundamental cellar should be large and clean, the square pillars whitewashed, and the bins for coal and potatoes and trunks convenient.†
Chpt 34

However impatient he may have been with her blandness he said readily: "Yes, guess I better do that.†
Chpt 38 *

Definitions:

(1) (however as in: However, complications may...)
though (or another expression that connects contrasting ideas)

(Based on idea 1 we might not expect idea 2, but this is a way of saying that even though idea 1 exists, we still have idea 2. Synonyms include in spite of that, despite that, nevertheless, nonetheless, on the other hand, in contrastand but.)
(2) (however as in: However much she tried...)
to whatever degree (regardless of how much; or whatever unspecified amount)
(3) (however as in: However you do it, get it done!)
in whatever way
(4) (meaning too rare to warrant focus)
meaning too rare to warrant focus:

Much more rarely (and arguably incorrectly), however can be used to intensify the word how, as when one says "However did you find her?" Grammarians would suggest using two words for that usage: "How ever did you find her?"