It's strong and seemingly effortless (4)

I believe the answer is:

fort

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

'it's strong' is the definition.
I can't judge whether this defines the answer.

'seemingly effortless' is the wordplay.
'FORT' is hidden within the letters.
But, I am uncertain how this is indicated.

'and' is the link.

Can you help me to learn more?

(Other definitions for fort that I've seen before include "Defensive stronghold" , "castle, perhaps" , "& 22 US Army post" , "US gold reserves are at - Knox" , "& 4 Down Army post in USA" .)

I've seen this clue in the Evening Standard.

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