What is a Smooth Word™?

If a word follows a single property, I call it a Smooth Word™. There isn't much of maths and/or encoding and stuff; it requires a bit of out-of-the-box thinking. Resemblance between words of each pair is intentional (so that you can compare similar words), but of no relevance to the actual answer.

SMOOTH WORDS™   NOT SMOOTH WORDS™
pentagon        police
infant          infantry
encryption      encrypt
technical       technique
ten             twenty
I               thy
water           slaughter
aces            ace
west            east
privately       publicly

• The word request thing won't work and wouldn't happen anyway – Beastly Gerbil Sep 22 '16 at 6:28
• @BeastlyGerbil Why? – ghosts_in_the_code Sep 22 '16 at 6:29
• First off most words suggested won't have the word property and if we were to submit words that do follow the rule we'd have to know the rule first, secondly 10 users for each word is way to high and thirdly it's just not really a great idea – Beastly Gerbil Sep 22 '16 at 6:31
• @BeastlyGerbil The words are a very common, it is easy to stumble upon them by chance. Ok no, I didn't mean 10 users for one word. I meant 10 users, each submitting their own pair of words. – ghosts_in_the_code Sep 22 '16 at 6:34
• For what it's worth, I completely disagree with @beastlygerbil that the words being common is a problem. As long as the rule is deterministic, challenging to find and somewhat interesting, it doesn't matter if there's ten or ten thousand words in the set. – Alconja Sep 22 '16 at 9:08

A word is SMOOTH if and only if the number of vowels it has is the same as the number of syllables.

For the purposes of this solution, the vowels are a, e, i, o, u (I'm not counting y as a vowel)

Examples

encryption has three vowels (e, i, o) and three syllables.
encrypt has one vowel (e) and two syllables.

technical has three vowels and three syllables.
technique has four vowels and two syllables.

• I think Y is considered a vowel in those words. – fdr Sep 22 '16 at 14:20
• @fdr I should be more specific. For the purpose of this solution, I do not count 'y' as a vowel. I'll add an extra line for clarification. – hexomino Sep 22 '16 at 14:23
• Cheers, correct answer. – ghosts_in_the_code Sep 22 '16 at 14:26