on second thoughts (prepphrase)
/ɑːn ˈsek·ənd θɑːts/

used when you want to change something that you have just said

out of date (adj)
/aʊt ɑv deɪt/

old and no longer suitable for modern processes, purposes, or methods

out of reach (prepphrase)
/aʊt ɑv riːtʃ/

outside the distance to which someone can stretch out their hand

out of danger (prepphrase)
/aʊt ɑv ˈdeɪn·dʒɚ/

not expected to die

out of use (prepphrase)
/aʊt ɑv ju:z/

to stop being used

out of the question (prepphrase)
/aʊt ɑv ðə ˈkwes·tʃən/

too impracticable or unlikely to merit discussion

out of order (idiom)
/aʊt ɑv ˈɔːr.dɚ/

not working properly or at all

under control (prepphrase)
/ˈʌn.dɚ kənˈtroʊl/

a danger or emergency such that people are able to deal with it successfully

under cover (prepphrase)
/ˈʌndɚ ˈkʌv·ɚ/

pretending to be someone else in order to find out secret information

out of work (prepphrase)
/aʊt ɑv wɝːk/

unemployed

by mistake (prepphrase)
/baɪ mɪˈsteɪk/

accidentally; in error

on the contrary (prepphrase)
/ɑːn ðə ˈkɑːn.tre·ri/

used for emphasizing that something is true, even though it is the opposite of something that has been said

on average (prepphrase)
/ɑːn ˈæv.ɚr.ɪdʒ/

used for talking about what is usually true, although it may not be true in every individual situation

on one's own (prepphrase)
/ɑːn wʌn's oʊn/

unaccompanied by others; alone or unaided

on purpose (prepphrase)
/ɑːn ˈpɝː.pəs/

if you do something on purpose, you do it intentionally, not by accident

on time (prepphrase)
/ɑːn tɑɪm/

arriving at the correct time and not late

on fire (prepphrase)
/ɑːn faɪr/

burning

on and off (prepphrase)
/ɑːn ənd ɔf/

sometimes but not regularly

by chance (prepphrase)
/baɪ tʃæns/

unexpected

within reach (prepphrase)
/wɪθˈɪn riːtʃ/

inside the distance to which someone can stretch out their hand