The person left holding the baby - and it won't be dropped! (6)
I believe the answer is:
sitter
'the person' is the definition.
(sitter is a kind of person)
'left holding the baby and it won't be dropped' is the wordplay.
I cannot quite see how this works, but
'it' could be 't' (abbreviation. e.g. in 'tis) and 't' is present in the answer.
'be' could be 'sit' (sitting is a kind of being) and 'sit' is located in the answer.
The remaining letters 'er' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for sitter that I've seen before include "eyed by a drawer?" , "Model - childminder" , "broody type" , "Child minder, sounds sedentary" , "one rarely missed?" .)