Lacking a purpose or a meaning (6)

I believe the answer is:

adrift

I'm a little stuck... Click here to teach me more about this clue!

'lacking a purpose' is the definition.
I can't judge whether this defines the answer.

'a meaning' is the wordplay.
'meaning' becomes 'drift' (drift is a kind of meaning).
'a'+'drift'='ADRIFT'

'or' acts as a link.

Can you help me to learn more?

(Other definitions for adrift that I've seen before include "Disoriented" , "without guidance?" , "Rudderless, astray" , "out of touch" , "Floating uncontrolled" .)

I've seen this clue in The Sunday Times.

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