Giant man comes in to pour tea without hesitation (8)
I believe the answer is:
behemoth
'giant' is the definition.
(synonyms)
'man comes in to pour tea without hesitation' is the wordplay.
'man' becomes 'he'.
'comes in to' means one lot of letters goes inside another.
'pour tea' becomes 'be mother' (to 'be mother' can informally mean to pour the tea).
'without' suggests deleting specific letters.
'hesitation' becomes 'er' (sound used when hesitating).
'bemother' with 'er' removed is 'bemoth'.
'he' placed inside 'bemoth' is 'BEHEMOTH'.
(Other definitions for behemoth that I've seen before include "A huge beast in the Bible" , "Huge animal as from the Bible" , "Monstrous beast, or thing" , "Huge or monstrous person or thing" , "Something abnormally large and powerful" .)