To sell something for less than its value.
To sell goods for a lower price than a competitor.
To put forward an idea, or to market a new product, with insufficient enthusiasm.
To assign a low value to (something).
To treat as a write-off, a total loss, especially something damaged beyond economic repair.
To record (an expenditure) as an expense.
To remove a portion of a debt or an amount of an account owed, counting it as a loss (as a gesture of goodwill for example).
To reduce the book value of (an asset) to zero.
To record a notional expense such as amortization or depreciation.