locksmith

noun

Etymology: From Middle English loksmith; equivalent to lock + smith.

1. One who practices locksmithing.

   “The door was very strong, the lock excellent; the carpenter avowed he would have great trouble and have to do much damage, if force were to be used; and the locksmith was near despair.”

   “Piccadilly, 12:30 o'clock.--Just before we reached Fenchurch Street Lord Godalming said to me, "Quincey and I will find a locksmith. You had better not come with us in case there should be any difficulty. For under the circumstances it wouldn't seem so bad for us to break into an empty house.”

2. Someone who only bets when they are sure they will win.