Posy suggesting one's head not all straight? (7)
I believe the answer is:
omnibus
I believe this clue is a quintuple definition!!
'posy' is the first definition.
(thesaurus)
'suggesting' is a link.
'one's' is the second definition.
(thesaurus)
'head not' is the third definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Maybe you can see an association between them that I don't see?
'all' is the fourth definition.
(thesaurus)
'straight?' is the fifth definition.
(thesaurus)
Can you help me to learn more?
(Other definitions for omnibus that I've seen before include "Anthology" , "Large vehicle - collected edition" , "A number of books in one" , "Compound volume" , "Charabanc" .)