Never disappearing outside, after dropping by (7)
I believe the answer is:
eternal
'never disappearing outside after dropping by' is the definition.
I can't tell whether this definition defines the answer.
'outside after dropping by' is the wordplay.
'outside' becomes 'external' (synonyms).
'after dropping' suggests deleting specific letters.
'by' becomes 'x' (2 by 4 is 2 x 4).
'external' with 'x' removed is 'ETERNAL'.
Can you help me to learn more?
(Other definitions for eternal that I've seen before include "Forever and always" , "'Lasting forever, unending (7)'" , "Forever or unchanging" , "Seemingly without end" , "Infinite - endless" .)