I couldn't find anything for this season, but Luguentz Dort, Aaron Wiggins and Jalen Williams were tied for losing the most games with the Thunder in 2024-25, with 14 losses.

Interpreted as:

most losses by a player for the thunder this regular season

	NAME	L	SEASON	TM	GP	MPG	PPG	RPG	APG	SPG	BPG	FGM	FGA	FG%	3PM	3PA	3P%	FTM	FTA	FT%	TS%	OREB	DREB	TPG	MIN	PTS	REB	AST	STL	BLK	TOV	PF	+/-
1	Luguentz Dort L. Dort	14	2024-25	OKC	71	29.2	10.1	4.1	1.6	1.1	0.5	3.6	8.4	43.5	2.4	5.8	41.2	0.5	0.6	71.7	58.6	1.3	2.9	0.7	2,073	719	293	115	79	39	51	208	+549
2	Aaron Wiggins A. Wiggins	14	2024-25	OKC	76	22.9	12.0	3.9	1.8	0.8	0.2	4.7	9.6	48.8	1.7	4.5	38.3	1.0	1.2	83.1	59.6	1.1	2.8	0.9	1,744	914	295	134	60	18	69	101	+512
3	Jalen Williams J. Williams	14	2024-25	OKC	69	32.4	21.6	5.3	5.1	1.6	0.7	8.2	16.9	48.4	1.8	4.9	36.5	3.4	4.3	78.9	57.3	0.9	4.5	2.2	2,237	1,490	369	354	111	46	150	158	+456
4	Shai Gilgeous-Alexander S. Gilgeous-Alexander	13	2024-25	OKC	76	34.2	32.7	5.0	6.4	1.7	1.0	11.3	21.8	51.9	2.1	5.7	37.5	7.9	8.8	89.8	63.7	0.9	4.1	2.4	2,598	2,484	379	486	131	77	183	164	+918
5	Cason Wallace C. Wallace	13	2024-25	OKC	68	27.6	8.4	3.4	2.5	1.8	0.5	3.4	7.2	47.4	1.1	3.1	35.6	0.4	0.5	81.1	56.2	1.0	2.3	0.9	1,876	568	229	173	120	35	59	145	+369
6	Kenrich Williams K. Williams	11	2024-25	OKC	69	16.4	6.3	3.5	1.4	0.6	0.1	2.5	5.1	48.3	1.0	2.5	38.6	0.4	0.6	71.8	58.7	0.9	2.6	0.6	1,132	436	241	97	43	10	39	110	+329
7	Isaiah Joe I. Joe	11	2024-25	OKC	74	21.7	10.2	2.6	1.6	0.6	0.1	3.5	7.9	44.0	2.6	6.3	41.2	0.6	0.8	82.1	61.7	0.6	2.1	0.5	1,604	756	196	119	48	9	38	113	+550
8	Alex Caruso A. Caruso	10	2024-25	OKC	54	19.3	7.1	2.9	2.5	1.6	0.6	2.6	5.8	44.6	1.1	3.1	35.3	0.8	0.9	82.4	56.8	0.7	2.2	0.7	1,041	382	159	137	87	30	37	102	+321
9	Dillon Jones D. Jones	9	2024-25	OKC	54	10.2	2.5	2.2	1.1	0.3	0.1	0.9	2.5	38.3	0.3	1.2	25.4	0.3	0.5	60.7	46.4	0.6	1.7	0.5	551	135	121	58	16	4	28	54	+75
10	Isaiah Hartenstein I. Hartenstein	8	2024-25	OKC	57	27.9	11.2	10.7	3.8	0.8	1.1	4.9	8.4	58.1	0.0	0.3	0.0	1.4	2.1	67.5	59.9	2.9	7.9	1.7	1,590	637	611	219	47	62	96	171	+417
11	Jaylin Williams J. Williams	7	2024-25	OKC	47	16.7	5.9	5.6	2.6	0.5	0.6	2.1	4.7	43.9	1.3	3.3	39.9	0.5	0.6	76.7	59.4	1.0	4.6	0.7	784	278	262	120	22	29	35	79	+302
12	Ousmane Dieng O. Dieng	7	2024-25	OKC	37	10.9	3.8	2.2	0.8	0.5	0.2	1.5	3.4	43.2	0.6	1.9	32.4	0.3	0.4	68.8	53.8	0.5	1.7	0.5	405	142	81	31	17	7	18	33	+45
13	Chet Holmgren C. Holmgren	6	2024-25	OKC	32	27.4	15.0	8.0	2.0	0.7	2.2	5.2	10.7	49.0	1.4	3.6	37.9	3.2	4.2	75.4	59.9	1.5	6.5	1.8	877	479	257	63	23	71	56	72	+294
14	Ajay Mitchell A. Mitchell	5	2024-25	OKC	36	16.6	6.5	1.9	1.8	0.7	0.1	2.5	5.1	49.5	0.6	1.7	38.3	0.8	1.0	82.9	58.7	0.5	1.4	0.8	597	234	68	64	25	4	29	68	+127
15	Adam Flagler A. Flagler	3	2024-25	OKC	37	5.5	1.8	0.7	0.3	0.2	0.1	0.7	2.6	26.0	0.4	1.9	19.4	0.0	0.1	50.0	33.5	0.2	0.5	0.1	203	65	27	12	8	3	4	15	+7
16	Branden Carlson B. Carlson	3	2024-25	OKC	32	7.7	3.8	1.7	0.4	0.2	0.7	1.3	3.0	44.3	0.7	2.1	33.3	0.4	0.6	77.8	58.1	0.5	1.2	0.2	246	122	54	14	5	21	7	22	+41
17	Alex Ducas A. Ducas	1	2024-25	OKC	21	6.0	1.7	1.2	0.2	0.2	0.0	0.6	1.4	40.0	0.5	1.0	47.6	0.1	0.1	100.0	58.3	0.4	0.8	0.2	125	36	26	5	5	0	4	12	-22