A pot slightly open (4)

I believe the answer is:

ajar

'slightly open' is the definition.
(as in a door left ajar)

'a pot' is the wordplay.
'pot' becomes 'jar' ().
'a'+'jar'='AJAR'

(Other definitions for ajar that I've seen before include "opened tentatively?" , "Part-open" , "Barely open" , "Mourn" , "Partly open" .)

I've seen this clue in The Telegraph.

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