Humble when welcomed to Lincoln? (5)
I believe the answer is:
abase
'humble' is the definition.
(synonyms)
'when welcomed to lincoln?' is the wordplay.
'when' becomes 'as' (eg 'when I walked' means 'as I walked').
'welcomed to' means one lot of letters goes inside another (inserted letters are welcomed inside).
'lincoln?' becomes 'abe' (Abraham Lincoln).
'as' going within 'abe' is 'ABASE'.
(Other definitions for abase that I've seen before include "Humble (oneself)" , "Humiliate" , "Degrade (oneself)" , "put to shame" , "Belittle, degrade" .)