estimate (verb) = to guess the value, amount, importance, etc. of something
Our journey is estamated to last for ten days.
impromptu (adjective) = said, done without previous preparation, improvised, spontaneous
I forgot the lyrics of the song, so I came up with new, impromptu words and no one has noticed.
unbeknowst (to sb) (adverb) = without a particular person knowing
Unbeknowst to me, she had sold all my CDs while I was on my vacation trip.
increment (noun) = one of a series of increases, small step toward gain, accretion
You will receive annual pay increments every December.
pound (verb) = to crush something, beat rhythmically, to hit or beat repeatedly with a lot of force
He was pounding away on his laptop until four in the morning, when he eventually finished the project.
redeem (verb) = to improve, repay, pay off, to get something back, to make something seem less bad
She saved enough amount of money, so that she could redeem her jewelry from the pawnshop.