Definitely is pronounced DEF-ə-nət-lee (IPA /ˈdɛfənətli/). Stress 'DEF'; all middle vowels reduce to a quick schwa.
IPA: /ˈdɛfənətli/
Syllables: DEF · ə · nət · lee
Common ESL mistake: Learners say 'def-IN-ate-ly' with wrong stress and an 'ate' sound.
Tip: Stress 'DEF'; all middle vowels reduce to a quick schwa.