Agent carrying papers, here essentially marked with angular lines? (7)
I believe the answer is:
spidery
'marked with angular lines?' is the definition.
The answer and definition are not the same part of speech. However, adjectives and past participle verbs can occasionally define each other.
'agent carrying papers here essentially' is the wordplay.
'agent' becomes 'spy' (spy is a kind of agent).
'carrying' indicates putting letters inside.
'papers' becomes 'ID' (identity papers).
'essentially' indicates the central letters.
The middle letters of 'here' are 'er'.
'id'+'er'='ider'
'spy' enclosing 'ider' is 'SPIDERY'.
Can you help me to learn more?
(Other definitions for spidery that I've seen before include "Like a hand" , "Gangly" , "recalling web designers?" , "thin, angular style" , "(Of writing) thin and straggly" .)