The most common and most likely answer to this crossword clue is the 7 letter word GOLIATH
G
O
L
I
A
T
H
More clues leading to the result GOLIATH
- Huge fellow I look up in biblical city
- Giant pig about to carry dog around
- Giant success? End up with hotel
- Monster dog disturbs pig, rising
- Philistine‘s end in piggyback
- Boorish fellow about to follow retiring giant
- Climbing back into pig monster
- Swine holding queue up is a giant of a man
- Giant pig carrying dog around
- Big man that lost energy on train after lift heading for home
Buddy explains!

The straight part
We know that "Big man that lost" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case big man that lost = goliath.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.