In thrall and enthrall are easily confused terms. One is a phrase, the other is a word.
The spell-check application of most word processing software programs would not catch a slip-up of these two words. Spell-check is looking for words that aren’t in its dictionary, and words that resemble words in its dictionary but are possibly spelled wrong. Spell-check isn’t perfect. It doesn’t know and can’t guess what word you wanted or what word you meant, it can only judge the words on the page. If you used words that are all spelled correctly, it gives you a pass anyway.
Autocorrect suggests words that start with the same letters. It’s suggesting what word you may want to save time, but quite often, its suggestions are pretty off base. They don’t help you out, but they do make you laugh.
In thrall (pronounced “ihn” (pause) “thrawl”) is a noun phrase. It means to be influenced, or under the control of. Thrall means servitude, influence, the “in” indicates there may or may not be have been much choice in the matter.
Enthrall (pronounced “ihnthrawl”) is a verb. It means to captivate someone else, or multiple people through charm, magnetism, and confidence. To “be enthralled with” is another way for someone to say he/she is under someone else’s spell, or feeling charmed by the enthralling person.
The following story uses both words correctly:
Intan aimed to enthrall Enton with her charms and attention. She was always thinking of ways to raise his public profile and eagerly suggested them. Enton was flattered.
His friends weren’t seeing him as often. He always said he had plans for weeks out, and always with Intan. Unsure of Intan’s motives, his friends considered staging something like an intervention. They missed the old Enton; they suspected that Enton was in thrall and didn’t realize it.