IPA: /ˈtuːlər/
KK: /ˈtuːlər/
A person who uses tools, especially in a skilled way, or someone who commits fraud using machines.
The tooler was caught trying to steal money from the machine.
This word originates from Old English 'tōl', meaning an instrument or implement used to carry out a task. The suffix '-er' indicates a person who uses or is associated with that tool. Therefore, 'tooler' refers to a person who uses tools.
Think of someone who uses an 'instrument' ('tōl') to get a job done — that's what a 'tooler' is.