What was the use of the final letter in muff, and why take the trouble to write tough when tuf would do as well?
Either the first letter may be accommodated to the second, tuf, or the second may be accommodated to the first, tupt.
Hence arises a process of accommodation by which the word becomes either tupt or tufth (tuf).
tuff, tuf, n. generally volcanic tuff, the name given to the comminuted rock-dbris ejected from a volcanic orifice.
tuf a baronet, with four thousand a year if he's a shilling.