The most common and most likely answer to this crossword clue is the 12 letter word INTRANSITIVE
I've seen this crossword clue in The Times
I
N
T
R
A
N
S
I
T
I
V
E
More clues leading to the result INTRANSITIVE
Buddy explains!

The straight part
We know that "type of verb" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case type of verb = intransitive.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.
What does INTRANSITIVE mean?
INTRANSITIVE adjective- (grammar, of a verb) not transitive: not having, or not taking, a direct object
- Not transitive or passing further; kept; detained