To Miss An Event
To Fail To Do, To Fail To Have
transitive verb, godan verb
Remember how 欠 means lack? This verb is related – it's like you're causing yourself to lack something. It can mean to miss an event, so the thing you cause yourself to lack is an experience. It can also mean to fail to do something, or to fail to have something, depending on the context.
You can remember it this way: Since you cause yourself to lack something with this word, it's all your fault. That's why you want to cuss (かす). You made yourself miss out on something. Well $*%!!!
Since this word consists of a kanji with hiragana attached, you can bet that it will use the kun'yomi reading. You learned this reading already so you should be able to read it!
服用を欠かす
to miss a dose
食事を欠かす
to miss a meal
ランニングを欠かす
to miss a run
イメージトレーニングとじゅんびうんどうは欠かすな！
Don’t miss warming up with some visual training.
どの社いんもみんな、トーフグにとって欠かすことのできない社いんです。
All workers are indispensable for Tofugu.
私の生活に、携帯電話を欠かすことはできない。
I cannot live without my cell phone.