take off
phr. v..phr. v.. to leave the ground and begin to fly, or to leave a place suddenly.
phr. v.. to become airborne; by extension, to depart a location abruptly or to achieve a sudden increase in popularity or success.
The plane takes off at six in the morning.
After the meeting ended, he took off without saying goodbye to anyone.
The startup's valuation took off following the successful launch of their flagship application in the European market.
when used for aircraft, it is intransitive; when used for clothing, it is transitive and separable.
this is a polysemous phrasal verb; focus first on the literal 'airplane' sense before introducing the 'remove clothing' or 'sudden success' meanings.
The plane took of.The plane took off.the particle 'off' requires a double 'f'; 'of' is a preposition with a different function.