OK A1

/ˌoʊˈkeɪ/ Satisfactory; good enough but not excellent.

else A1

/ɛlts/ Other; in addition to or different from what has already been mentioned.

alien B2

/ˈeɪ.li.ən/ A creature from another planet or from outer space.

ultimate B2

/ălʈɪmeʈ/ The greatest or most extreme possible.

alter B2

/ˈɔl.təɹ/ To change something, or make it different.

alternate B2

/ɔlʈə(r).neʈ/ To do two things one after the other, by turns.

adulterate C2

/əˈdʌltəɹət/ To make something weaker or lower in quality by adding another substance.