Incorrect spelling, explanation: supliment is an incorrect form because it strays too much from the Latin original word supplementum. While it happens in English that words change vowels, there is no reason for the i to appear in this word.

Correct spelling, explanation: supplement is the correct spelling of the word because it has its roots in the Latin word supplementum. In the case of words borrowed directly from Latin, the spelling rarely changes drastically, except for being better suited to English, which is why the characteristic ending entum was lost, but the rest of the word stayed unchanged.

Definition of supplement:
Noun
1. An addition to something, usually added with an intention to make it better or complete, an extra
Fresh fruit is a great supplement to a busy person’s everyday diet.
2. An added part in books, magazines, or dictionaries, added for clarification, with extra information, or as advertisements.
The dictionary came with a supplement containing the most current neologisms.
Verb
1. To add something extra to something
It’s going to be a busy night, so we supplemented the staff with two additional workers.

Incorrect spelling

Incorrect spelling

Incorrect spelling

Incorrect spelling

Incorrect spelling

Incorrect spelling