Old Bob's inclined to be very formal (7)
I believe the answer is:
stilted
'very formal' is the definition.
'stilted' can be an answer for 'formal' (thesaurus). I am not sure about the 'very' bit.
'old bob's inclined' is the wordplay.
'old bob' becomes 's' (abbreviation for bob or shilling used before 1971).
'inclined' becomes 'tilted' ('tilted' can be similar in meaning to 'inclined').
's'+'tilted'='STILTED'
'to be' is the link.
Can you help me to learn more?
(Other definitions for stilted that I've seen before include "Bombastic (of speech, writing)" , "Stiff, self-conscious" , "Artificially formal or contrived" , "Awkward" , "Stiff and unnatural" .)