The phrase "make up top head" is commonly misspelled as "make up out of thin air". The correct spelling is "make up off the top of one's head". The IPA phonetic transcription for this phrase is /meɪk ʌp ɒf ðə tɒp əv wʌnz hɛd/. The phrase means to come up with something quickly, without much thought or preparation. The correct spelling is important for clear communication and professional writing.