This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
歒 combines 啇 and 欠. The exact historical development is uncertain, and the character is rare in modern Japanese.
The left side 啇 looks like a stand with a mouth, and the right side 欠 suggests a person yawning or lacking. Imagine someone standing speechless, yawning in confusion because the meaning is unclear.
For テキ, imagine a confused person holding a teakettle (teak -> テキ) while yawning, unsure what to do with it.