IPA: /ˈlɛŋθi/
KK: /ˈlɛŋθi/
Something that is very long in time or distance, often to the point of being boring or tedious.
The meeting was lengthy and seemed to go on forever.
Lengthy → It is formed from "length" (from Old English "length", meaning the measurement of something from end to end) and the suffix "-y" (meaning characterized by or having the quality of). The word "lengthy" describes something that has the quality of being long or extended in duration.
Think of the word 'length' which refers to how long something is, and remember that 'lengthy' means having the quality of being long.