Correct spelling, explanation: flexible is a word that can be taken apart as the base word flex and the suffix -ible. There is just one catch – there is also a similar suffix, -able, so how do you know which one to use? If you think about it, most words use -able, only some use -ible. The rule is that certain words of Latin origin and words without a clear root word; the number of words ending in -ible is fixed, while -able can be used in creating new words.

Definition of flexible:
adjective
1. possible to bend without breaking
Lately, I’ve been buying a lot of sports t-shirts made out of flexible materials that fit my body while being very comfortable.
2. possible to change and adapt to the situation
Cara can be very serious with some clients, and friendly with others, depending on what’s needed. She’s a very flexible worker.

Incorrect spelling, explanation: flexable is an incorrect item and the word should be spelled: flexible. The suffix -able is very useful and common, which is why it may be the first instinct to use it here. The number of words using the suffix -ible is limited, and new words are generally made without using it; this group contains words of Latin origin and words which don’t have a proper base word, like edible. The word flex in flexible is of Latin origin, which explains its spelling.